GENERAL  ARRANGEMENT  OF  WESTINGHOUSE  BRAKE 


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THE 

Air  Brake  Catechism 

AND 

INSTRUCTION  BOOK  ON  THE  CONSTRUCTION 
AND  OPERATION  OF 

THE  WESTINGHOUSE  AIR  BRAKE  and 
THE  NEW  YORK  AIR  BRAKE 

WITH  A  LIST  OF 

EXAMINATION  QUESTIONS  FOR  ENGINEMEN 
AND  TRAINMEN      ' 

BY 


• 


Copyrighted  by  CLINTON  B.  CONGER,  Grand  Rapids,  Mich. 
nberlS,  1906. 

' 

or  THP 


PREFACE. 

In  this  enlarged  edition  of  the  Air  Brake  Catechism 
considerable  new  matter  has  been  added  which  will  prove 
of  interest  not  only  to  those  who  are  learning  about  the 
operation  of  the  brake  equipment  from  their  own  obser- 
vation and  experience,  but  to  those  who  have  the  advan- 
tage of  an  instruction  car  with  a  regular  instructor.  This 
subject  of  self-instruction  in  all  its  details  is  so  large  that 
only  a  small  part  of  it  can  be  taken  up  in  this  little  book, 
but  the  principal  points  are  brought  to  notice. 

The  construction  and  operation  of  the  air  pump,  as  far 
as  it  interests  enginemen,  is  explained,  the  matter  of  re- 
pairs is  not  taken  up.  in  Q  *J  /  fi 

The  construction  and  operation  of  the  New  York  Air 
Brake  Company's  equipment  is  explained  in  addition  to 
that  of  the  Westinghouse  Air  Brake  Company. 

At  the  present  day  every  one  connected  with  the  work- 
ing of  the  air  brake  is  expected  to  pass  regular  examina- 
'tions,  and  these  examinations  are  getting  more  strict  each 
year.  The  work  done  by  the  air  brake  operator  in  hand- 
ling trains  is  becoming  more  skillful  every  year;  he  who 
wishes  to  keep  up  with  the  best  practice  must  continually 
try  to  improve  his  work.  This  can  only  be  done  by  learn- 
ing and  practising  the  best  methods. 

The  list  of  examination  questions  will  call  attention  to 
points  in  the  construction  and  handling  of  the  brake  which 
you  should  know  if  you  wish  to  pass.  Bear  in  mind  that 
good  judgment  is  the  first  requisite  for  a  successful  air 
brakeman,  the  addition  of  knowledge  of  the  construction 
so  as  to  locate  defects  and  their  remedies,  and  correct 
methods  of  handling,  to  good  judgment,  will  make  a 
skillful  man  under  all  conditions. 


INTRODUCTION. 

At  the  present  day  so  much  depends  on  the  proper 
handling  of  the  Automatic  Brake  that  a  definite  knowledge 
is  required  from  all  men  in  train  service  of  its  operation 
when  in  good  order,  and  how  to  locate  defects  or  break- 
downs, as  well  as  how  to  avoid  the  difficulties  arising  from 
them. 

This  applies  to  the  veteran  as  well  as  to  the  beginner. 
The  changes  in  the  mechanism,  caused  by  the  new  and 
improved  devices  brought  into  service  to  take  care  of 
longer  freight  trains  and  faster  passenger  trains,  call  for 
study  on  the  part  of  the  men  who  have  handled  the  brake 
for  years,  for  a  passenger  train  of  moderate  length  equipped 
with  ordinary  triple  valves  and  a  long  train  with  all  high 
speed  brakes  are  two  widely  different  propositions,  and  the 
veteran  looks  for  information  on  them.  As  for  the  be- 
ginner, he  can  not  learn  it  all  from  experience,  as  no  one 
is  allowed  to  handle  important  trains  until  he  has  shown, 
either  by  an  examination  or  by  handling  a  moving  train 
under  the  supervision  of  some  man  who  can  judge,  that  he 
has  the  necessary  knowledge  to  properly  operate  the  brake 
under  all  ordinary  conditions. 

This  has  brought  about  a  demand  for  a  clear  and  prac- 
tical form  of  instruction  in  air  brake  practice,  not  so  much 
to  instruct  the  beginner  on  all  the  points  as  to  put  him  in 
the  way  of  learning  them  himself;  and  this  introductory 
chapter  is  intended  to  help  those  who  set  out  to  learn  the 
theory  and  have  a  chance  to  operate  the  brake  or  see  it 
operated.  This  can  best  be  done  by  learning  the  foun- 
dation principles  first,  studying  the  action  of  the  important 
primary  parts  of  the  machine ;  the  secondary  parts  will  then 
work  their  way  in  so  you  understand  the  whole  properly. 

1 797 1 8 


4  SELF    INSTRUCTION 

Much  time  may  be  wasted  by  beginning  at  the  wrong  end 
to  unravel  air  brake  operations.  If  you  are  too  hasty  and 
jump  at  conclusions,  you  may  be  wrong;  better  not  know 
anything  about  it  than  know  it  wrong.  Therefore,  take 
time  enough  at  first  to  learn  it  right;  you  will  never 
regret  it. 

There  is  nothing  mysterious  about  the  operation  of  the 
air  brake.  Each  part  has  its  own  duty  to  perform.  Take 
each  part  by  itself  and  study  it  up,  then  get  an  idea  of  its 
relation  to  the  other  parts,  and  you  will  find  out  that  it  is 
easy.  You  cannot  learn  it  all  at  once,  or  by  once  reading 
over  an  instruction  book.  In  studying  the  construction 
and  principle  on  which  it  operates,  it  is  an  advantage  to 
have  help  from  some  one  who  can  instruct  you.  When 
you  come  to  operate  it,  the  machinery  in  actual  operation 
is  the  best  instructor. 

When  you  see  the  air  brake  working  every  day,  some- 
times making  a  good  stop,  at  others  not  controlling  the 
train  as  you  think  it  should,  the  operation  may  seem 
mysterious,  but  it  is  governed  by  fixed  laws  of  mechanics 
and  forces.  If  you  take  pains  to  learn  these  laws  and 
about  the  forces,  and  examine  each  part  of  the  mechanism, 
it  will  be  clear  to  you. 

Attention  is  called  to  explanations  of  some  of  these 
operations  in  the  succeeding  pages  of  the  Air  Brake  Cate- 
chism. Many  of  these  operations  are  explained  in  more 
than  one  manner  in  connection  with  the  movements  of 
other  parts  of  the  apparatus. 

In  the  first  place,  all  the  parts  of  the  brake  which  are 
named  in  question  I  of  the  Catechism,  are  charged  with 
compressed  air,  which  comes  from  the  air  pump  to  the 
main  reservoir,  then  through  the  ports  in  the  brake  valve 
into  the  train  pipe  and  triple  valve,  from  there  it  passes 
through  the  feed  port  in  the  triple  valve  into  the  auxiliary 
reservoir  provided  for  each  complete  brake.  When  the 
brake  is  ready  to  operate,  the  pressure  is  equal  in  the  train 
pipe,  in  the  triple  valve  on  both  sides  of  the  triple  piston, 
and  in  the  auxiliary  reservoir.  When  you  change  the 


PLAIN     TRIPLE     VALVE  5 

relation  of  these  pressures  in  different  parts  of  the  equip- 
ment, the  effort  the  compressed  air  makes  to  equalize,  by 
the  high  pressure  air  pushing  against  the  low  pressure  air, 
moves  the  different  parts  of  the  air  brake  that  can  be 
moved  in  this  manner  away  from  the  high  pressures. 

When  it  is  once  fixed  in  your  mind  what  pressure  you 
have  in  each  place,  and  that  any  change  of  pressure  will 
cause  the  movable  parts  of  the  valves  to  change  their 
positions,  closing  some  of  the  openings  through  which  the 
air  can  pass  and  opening  others,  it  is  plain  that  the  next 
step  is  to  find  out  just  what  openings  the  air  must  pass 
through  at  each  operation,  whether  applying  or  releasing 
the  brake. 

When  studying  the  equalizing  processes  in  the  operation 
of  compressed  air  equipment,  remember  that  it  is  air  that 
flows  from  one  part  of  the  equipment  to  another  and  not 
pressure.  Pressure  is  only  a  condition,  air  is  a  substance 
or  material.  A  substance  can  flow  from  one  cavity  or  re- 
ceptacle to  another,  but  a  condition  can  not  flow  through 
an  opening.  When  compressed  air  flows  from  any  part  of 
the  equipment  to  another,  as  from  the  auxiliary  to  the 
brake  cylinder,  it  will  change  the  conditions  or  pressure 
in  these  places,  but  the  pressure  does  not  flow  either  way. 

It  will  take  away  much  of  the  mystery  of  equalization 
if  you  will  bear  these  facts  in  mind. 

We  will  take  up  the  plain  triple  valve  first,  as  the 
process  of  equalization  is  best  explained  with  it.  You 
will  notice  in  the  cut  on  next  page  of  the  plain  triple  valve 
in  the  position  for  charging  the  auxiliary  reservoir  and 
exhausting  the  air  from  brake  cylinder,  that  the  triple 
piston  5  is  the  dividing  line  when  the  pressures  are 
unequal ;  that  the  train  pipe  pressure  is  against  the  lower 
side  of  this  piston  and  auxiliary  pressure  on  top.  There  is 
ja.  small  passage  cut  in  the  side  of  the  cylinder  around  the 
piston,  called  a  feed  -port,  at  m,  through  which  air  can 
pass  from  the  train  pipe  around  the  piston  5,  and  up  beside 
the  slide  valve  6  into  the  auxiliary  at  Y,  when  triple  piston 
is  clear  up  in  release  position;  this  is  the  opening  through 


PLAIN     TRIPLE     VALVE 


which  air  can  equalize  in  train  pipe  and  auxiliary.  The 
piston  acts  as  a  valve  to  open  and  close  this  feed  port. 
This  port  m  is  very  small,  and  equalization  takes  place 
slowly  through  it.  A  brief  explanation  of  the  reasons  for 
its  small  size  is  found  farther  along  in  the  book. 

As   the   auxiliary   stores   the   compressed   air   used   for 
applying  its  own  brake,  it  must  first  be  charged  with  a  full 


OF.TAILS 

Triple-Valve  Body 
Cylinder  Cap. 
Cap  Nut. 
Piston 
Slide  Valve. 
Graduating  Valve. 
Graduating  Stem. 
Graduating  Spring 
Graduating-Stem  Nu 
Cylinder  Gasket 
Packing  Ring. 
Bolt  ami  Nut. 
Slide-Valve  Spring 


RELEASE  AND  EXHAUST   POSITION. 

supply  of  air;  which  will  raise  its  pressure  to  the  standard 
— usually  70  pounds — and  it  takes  about  a  minute  and  10 
seconds  for  air  enough  to  flow  around  the  piston  to  equal- 
ize the  pressure  at  70  pounds.  To  apply  the  brake  with  a 
triple  valve  the  train  pipe  pressure  must  be  reduced.  As 
soon  as  any  reduction  of  pressure  is  made  in  the  train  pipe, 


SERVICE    APPLICATION  7 

the  auxiliary  pressure  will  be  greater  and  force  the  triple 
piston  down,  following  the  decrease  of  pressure  in  train 
pipe  end  of  triple. 

This  first  movement  of  the  piston  does  not  set  the  brake. 
There  is  some  slack  between  the  collar  on  the  piston  rod 
and  the  top  of  slide  valve  6 — about  five  thirty-seconds  of 
an  inch — a  very  slight  reduction  of  pressure  under  the 
piston  moves  it  down  the  amount  of  this  slack,  closing  feed 


SERVICE    APPLICATION — LAP    POSITION. 

port  m  and  pulling  graduating  valve  7  off  its  seat  in  slide 
"valve.  As  the  slide  valve  has  the  auxiliary  pressure  hold- 
ing it  on  its  seat,  more  change  of  pressure  under  the  piston 
is  needed  to  move  the  slide  valve — a  point  to  remember 
when  you  move  the  triple  valve  to  release  position.  When 
the  piston  comes  down,  bringing  with  it  the  slide  valve,  a 
port  zf  leading  from  the  seat  of  graduating  valve  7,  is 


8  SERVICE    APPLICATION 

opened  to  /,  allowing  the  auxiliary  air  to  pass  from  the 
graduating  valve  into  the  brake  cylinder.  This  also  has  a 
movable  piston  that  pushes  against  levers  which  are  so 
coupled  up  that  the  brake  shoes  are  forced  against  the 
wheels.  The  operation  of  this  triple  piston  with  a  moderate 
reduction  of  train  pipe  pressure,  say  from  70  pounds  down 
to  63,  will  show  the  exactness  of  this  equalization  prin- 
ciple. 

When  the  triple  piston  5  comes  down,  following  a 
reduction  of  7  pounds  in  the  train  pipe  (and  the  piston  does 
not  wait  till  the  entire  reduction  of  7  pounds  is  made),  and 
slide  valve  6  and  graduating  valve  7  opens,  the  air  in  the 
auxiliary  at  70  pounds  begins  to  expand  into  the  brake  cyl- 
inder, as  shown  in  cut  of  service  application.  As  soon  as 
enough  air  has  gone  into  the  cylinder  to  reduce  the  aux- 
iliary pressure  a  little  below  63  pounds,  the  train  pipe  pres- 
sure is  then  greatest;  hence  triple  piston  moves  up,  also 
moving  the  graduating  valve  7  and  closing  it.  This  cuts 
off  the  flow  of  air  into  the  brake  cylinder.  As  only  a  part 
of  the  full  supply  of  air  has  passed  into  the  brake  cylinder, 
it  sets  the  brake  with  a  partial  application  and  holds  it  set, 
for  the  piston  does  not  move  the  slide  valve  6  up  and  open 
the  exhaust  port  k  to  air  port  f,  as  shown  in  cut  of  release 
position.  For  a  more  detailed  statement  of  the  operation 
of  the  graduating  valve,  see  the  answer  to  a  question  far- 
ther along  in  this  book.  Thus  you  see  the  triple  piston 
moves  between  the  train  pipe  and  auxiliary  pressures,  al- 
ways towards  the  lesser  one. 

A  graduating  stem  8  and  its  spring  9,  in  the  bottom 
case  of  the  triple,  serve  to  stop  the  piston  at  a  point  in  its 
travel  where  port  z  will  be  exactly  opposite  port  f.  This 
stem  and  spring  are  not  moved  in  a  partial  service  appli- 
cation, because  when  these  ports  are  wide  open  the  air  will 
pass  from  the  auxiliary  to  the  cylinder  as  fast  as  it  is  going 
out  of  the  train  pipe,  this  will  reduce  the  auxiliary  pressure 
as  fast  as  the  train  pipe  pressure  reduces. 

If  the  relations  between  the  pressures  on  either  side  of 
triple  piston  are  changed,  it  will  move  toward  the  lower 


RELEASING    BRAKES 


pressure  until  the  limit  of  its  travel  is  reached,  or  until  the 
relation  between  the  pressures  is  changed  the  other  way; 
this  .will  stop  its  movement  if  pressures  are  equalized,  or 
move  it  the  other  way  if  pressure  is  increased.  Increasing 
the  pressure  in  train  pipe  side  of  triple  over  the  auxiliary 
moves  the  triple  piston  clear  up,  moves  the  slide  valve  6, 
opens  exhaust  port  k  to  air  port  f,  allows  the  air  to  escape 


The  plain  triple  valve 
moves  t  o  this  position 
when  the  train  pipe  pres- 
sure is  lower  than  the 
equalizing  pressure  of  the 
cylinder  and  auxiliary 
either  with  a  quick  or  a 
slow  reduction. 


EMERGENCY  APPLICATION. 

from  brake  cylinder  and  releases  the  brake;  so  you  see, 
charging  up  the  train  pipe  to  standard  pressure  releases 
the  brake.  As  the  feed  port  m  is  also  opened  when  the 
piston  5  is  clear  up,  the  air  flows  into  auxiliary,  equalizing 
its  pressure  with  the  train  pipe.  To  change  the  relations 
between  the  pressures  in  any  other  way  is  done  by  letting 
out  some  of  the  air — the  train  man  releases  the  brake  by 


IO  EMERGENCY    APPLICATION 

bleeding  out  the  auxiliary  pressure  until  it  is  lower  than 
train  pipe  pressure. 

If  a  reduction  of  the  train  pipe  pressure  of  more  than 
20  pounds  is  made,  as  from  70  to  below  50,  the  auxiliary 
pressure  must  also  be  reduced  20  pounds  or  more  before  it 
will  allow  the  piston  5  to  move  up  and  close  the  graduating 
valve. 

The  brake  cylinder  is  of  such  a  size — if  it  has  the  proper 
piston  travel — in  proportion  to  the  auxiliary  reservoir  that 
if  air  is  allowed  to  flow  from  the  auxiliary  into  the  cylinder 
it  will  equalize  in  both  of  them  at  about  five-sevenths  of 
the  original  pressure,  which  is  50  pounds  in  case  of  70 
pounds  originally.  After  this  equalization  has  taken  place 
no  more  reduction  of  pressure  will  be  made  in  the  reservoir 
except  by  a  leak  or  at  the  bleeder  and  the  triple  piston 
will  move  clear  down  to  the  position,  which  with  a  gradual 
service  application  is  called  full  application  position.  This 
is  the  same  as  the  emergency  application  position.  You 
will  notice  the  slide  valve  has  uncovered  the  air  port  /  so 
air  can  pass  through  freely  and  hold  the  brake  cylinder 
pressure  equal  to  the  auxiliary  pressure.  The  stud  or  post 
on  the  bottom  of  triple  piston  has  pushed  the  graduating 
stem  8  down,  compressing  its  spring  p.  This  spring  helps 
to  stop  the  piston  5  at  the  proper  place  with  a  partial  service 
application  and  assists  in  starting  the  piston  up  to  release 
after  a  full  application. 

After  thoroughly  posting  yourself  on  the  way  in  which 
the  plain  triple  operates  by  the  reduction  or  equalization 
of  pressures,  you  can  then  take  up  the  engine  equipment. 
It  is  a  good  plan  to  know  just  how  the  pump  operates,  its 
care  and  management,  but  that  can  be  left  till  later;  it  is 
treated  of  farther  along  in  this  book.  The  pump  generally 
goes  ahead  with  its  work  from  beginning  to  end  of  the 
trip  without  much  attention  from  the  engineer;  the  rest 
of  the  equipment  depends  on  the  skill  and  knowledge  of 
the  engineer  for  its  successful  operation,  as  it  responds 
directly  to  his  manipulation. 
,  The  brake  valve  controls  the  passage  of  air  between  the 


THE   BRAKE   VALVE,  II 

main  reservoir  and  train  pipe,  or  train  pipe  and  the  at- 
mosphere. 

The  main  reservoir  air  pressure  is  always  in  the  top  of 
the  valve  holding  the  rotary  valve  13  on  its  seat;  the  train 
pipe  air  is  under  the  equalizing  piston  17  at  all  times. 
The  air  over  the  piston  can  be  called  brake-valve  air.  Brake 
valve  and  train  pipe  air  can  equalize  when  the  rotary  is  on 
running  position,  and  in  full  release.  This  is  further  ex- 
plained in  detail  later  on.  The  equalizing  piston  77  is 
moved  up,  opening  the  discharge  or  train  pipe  exhaust  port 
n,  or  down,  closing  the  port,  by  a  change  of  pressure  on 
either  side,  just  the  same  as  the  triple  piston.  The  pres- 
sures are  changed  by  opening  or  closing  the  various  ports 
in  the  valve.  Opening  preliminary  exhaust  port  h  reduces 
the  pressure  over  piston  17  so  that  train  pipe  pressure 
raises  the  piston ;  train  pipe  pressure  reducing  through  port 
n  brings  piston  down.  The  rotary  13  is  moved  by  the 
engineer,  its  office  is  to  put  in  communication  the  various 
openings  or  ports  that  will  let  the  air  pass  through.  Locate 
these  ports, next  find  out  just  what  they  are  for  and  in  what 
positions  of  the  rotary  they  are  open  and  shut.  The  best 
way  to  do  this,  if  you  have  no  sectional  valve  to  study  on,  is 
to  get  a  complete  valve  for  a  few  hours  and  dissect  it,  using 
a  piece  of  fine  copper  wire  to  run  through  the  ports,  which 
will  show  the  course  of  the  air;  this  wire  can  be  bent  in 
any  direction  and  its  use  is  not  likely  to  scratch  the  seats 
or  valve.  After  locating  all  the  ports  through  which  main 
reservoir  air  can  flow  into  train  pipe  or  the  chamber  D  over 
piston  77,  then  see  in  what  position  of  the  rotary  all  ports 
are  covered,  and  figure  out  which  ports  are  covered  first 
and  why  it  is  necessary  to  stop  the  flow  of  air  through 
them. 

You  will  probably  notice  that  before  any  ports  are 
opened  to  allow  air  to  escape  from  the  train  pipe  the  main 
reservoir  air  is  cut  off  from  the  train  pipe,  so  it  can  not 
supply  the  train  pipe  while  you  are  reducing  that.  Other- 
wise the  triple  valve  would  not  feel  any  reduction  of  pres- 
sure and  brake  would  rrot  t>e  set.  Then  when  you  come  to 


THE   BRAKE  VALVE  13 

locate  the  ports  that  are  opened  to  reduce  the  train  pipe 
pressure  and  actuate  the  triple,  it  will  be  necessary  to  know 
just  exactly  the  principle  of  operation  of  the  equalizing 
discharge  valve. 

On  a  long  train  the  reduction  of  train  pipe  pressure 
must  be  the  same  at  each  triple  if  we  expect  each  brake 
to  be  set  at  the  same  time  and  with  the  same  relative 
power.  To  make  this  reduction  of  pressure  alike  for  all 
the  triples,  or  what  is  the  same,  for  all  the  cars  in  the 
train,  we  must  allow  the  air  to  escape  from  the  train 
pipe  gradually  so  the  reduction  will  not  be  any  more 
violent  from  the  first  car  than  from  the  last  one,  nor  should 
the  escape  of  air  be  closed  till  the  same  reduction  has  been 
made  in  each  car.  The  discharge  should  not  be  stopped 
suddenly  before  the  pressure  in  the  last  cars  has  equalized 
with  the  first  ones,  or  the  momentum  of  air  flowing  from 
rear  cars,  as  well  as  equalizing  pressures  in  all  cars,  will 
raise  the  train  pipe  pressure  in  the  cars  nearest  the  brake 
valve  and  tend  to  release  their  brakes.  This  gradual  clos- 
ing of  the  train  pipe  exhaust,  the  brake  valve  is  intended 
to  do  automatically.  Its  principle  of  operation  is,  the 
engineer  makes  the  proper  reduction  of  pressure  in  the 
brake  valve  over  the  equalizing  piston  77,  and  the  action 
of  the  piston  17  reduces  the  train  pipe  pressure  to  an  equal 
amount  in  all  the  cars,  whether  few  or  many. 

Before  you  move  the  rotary  far  enough  to  open  the 
preliminary  exhaust  port  h,  the  equalizing  port  g,  which 
allows  train  pipe  air  to  pass  from  train  pipe  to  chamber  D, 
over  piston  77,  is  closed ;  this  cuts  off  chamber  D  from  any 
other  pressure;  you  can  then  make  a  reduction  on  top  of 
piston  77,  so  train  pipe  pressure  will  raise  it  up  and  hold 
discharge  n  open  till  the  pressure  below  is  a  little  less  than 
it  is  above,  when  piston  is  moved  down  by  the  chamber  D 
pressure,  closing  train  pipe  discharge 

With  the  equalizing  discharge  valve,  the  black  hand 
of  the  double  gage  is  connected  with  chamber  D  at  all 
times ;  if  the  rotary  is  in  either  full  release  or  running  po- 
sition the  equalizing  port  g  connects  it  to  the  train  pipe  air, 


14  THE   BRAKE   VALVE 

so  it  shows  that  pressure  also.  When  the  brake  is  set 
with  a  service  application,  the  pressures  equalize  so  nearly 
on  each  side  of  piston  at  the  instant  train  pipe  exhaust 
closes  that  the  black  hand  is  expected  to  show  train  pipe 
pressure  then  also.  In  the  emergency  position  the  black 
hand  does  not  at  once  show  the  amount  of  trie  reduction. 
You  will  find  this  further  explained  later. 

If  the  packing  ring  in  piston  17  leaks  very  much,  the 
black  hand  will  show  train  pipe  pressure  when  rotary  is 
on  lap,  as  the  air  pressures  can  equalize  past  this  leaky 
packing  ring;  all  of  them  leak  a  little.  Look  out  for  this 
defect  when  operating  the  brake.  The  brake  valve  reser- 
voir is  connected  with  the  valve  for  the  purpose  of  giving 
a  larger  volume  of  air  to  chamber  D  in  order  to  insure  a 
gradual  reduction  of  pressure  there. 

Up  to  this  point  we  will  assume  that  the  student  has 
followed  the  action  of  the  brake  in  a  service  or  graduated 
application.  There  is  what  we  call  the  emergency  or  quick 
action,  which  is  produced  by  a  different  set  of  operations 
and  is  peculiar  to  the  quick  action  triple  valve  only.  We 
will  go  to  the  beginning  and  inquire  why  this  action  is 
necessary. 

On  a  long  train  of  air  braked  cars,  to  avoid  a  severe 
shock  to  the  rear  part  of  train  when  brakes  are  applied 
from  the  head  end  of  train  very  suddenly,  as  by  bursting 
a  hose  or  breaking  apart  of  the  train,  or  in  case  of  danger 
when  it  is  necessary  to  set  the  brake  brom  the  Engine  very 
hard  so  as  to  stop  as  quickly  as  possible,  the  brakes  should 
set  on  the  rear  cars  quickly  enough  so  the  slack  will  not 
run  up  against  head  cars  and  damage  cars  or  draft  gear. 
Then,  in  case  of  danger,  every  second  after  the  brake  is 
applied  at  the  engine  before  it  begins  to  set  on  last  cars 
and  hold  them,  the  train  is  getting  nearer  the  danger;  so 
a  brake  that  can  be  set  instantly  on  the  whole  train  will 
stop  the  train  quicker  than  one  which  sets  slowly  from  car 
to  car.  With  the  plain  triples  the  air  in  train  pipe  will  be 
exhausted  at  one  place  only,  either  where  an  opening  is 
made  in  train  pipe  or  at  brake  valve;  this  takes  several 


THE   TRIPLE   VALVES 


seconds  to  affect  the  farthest  car.  If  an  opening  can  be 
made  to  exhaust  this  air  at  each  car  and  reduce  the  train 
pipe  pressure,  the  action  of  the  brakes  on  a  long  train  can 
be  made  nearly  simultaneous,  so  nearly  so  that  the  brakes 
are  all  set  before  the  slack  can  run  out.  The  quick  action 


DETAILS. 

2  Triple  valve  body. 

3  Slide  valve. 

4  Piston. 

6  Slide-valve  spring. 

7  Graduating  valve. 


A] 

'TO  TRAIN  PIPE 


8  Emergency-valve  piston. 

9  Emergency-valve  semt. 

10  Emergency  valve. 

11  Rubber  seat. 

12  Check-valve  spring. 

13  Check-valve  case. 
15  Check  valve. 

21  Graduating  stem. 

22  Graduating  spring. 

QUICK -ACTION  TRIPLE  VAI/VE — RELEASE  POSITION. 

triple  is  designed  to  exhaust  a  portion  of  the  train  pipe  air 
at  each  triple,  so  as  to  set  the  next  brake  suddenly.  To 
thoroughly  understand  how  the  quick  action  triple  can 
exhaust  some  of  the  air  from  the  train  pipe  suddenly  and 
reduce  the  pressure  so  as  to  affect  the  next  triple  in  the 


l6  QUICK    ACTION    TRIPLE    VALVE 

same  manner,  it  will  be  necessary  to  study  the  construction 
of  the  quick  action  valve.  This  triple  has  the  same  open- 
ings to  admit  air  from  the  train  pipe  to  the  auxiliary  that 
we  find  in  the  plain  triple.  In  the  quick  action  triple  they 
are  shown  at  e  through  g  and  feed  port  i.  But  there  is 
another  channel  for  air  to  pass  from  the  train  pipe  into 
the  brake  cylinder  in  this  valve,  which  is  from  the  check 
valve  case  13  into  yt  then  into  x  and  into  brake  cylinder  at 
C.  These  openings  are  ordinarily  kept  closed  to  the  pass- 
age of  the  air  in  either  direction ;  the  rubber  seated  emer- 
gency valve  JO  keeps  the  train  pipe  air  from  getting  into 
the  cylinder,  and  the  check  valve  75  keeps  the  air  in  brake 
cylinder  from  getting  back  into  train  pipe.  These  two 
valves  are  held  on  their  seats  by  a  spring,  shown  at  12,  as 
well  as  by  the  air  pressures.  Now  it  follows  that,  if  you 
wish  this  triple  to  make  an  opening  to  let  the  air  out  of 
train  pipe  suddenly,  this  valve  10  must  be  moved  away 
from  its  seat  against  the  train  pipe  pressure  and  the  strain 
of  the  spring  12.  For  this  purpose  piston  8  is  used.  A 
port  t,  which  is  shown  just  over  the  figure  8,  can  be  opened 
by  the  slide  valve  3,  letting  the  air  from  the  auxiliary  on 
top  of  piston  8;  with  auxiliary  reservoir  pressure  over  this 
piston  and  no  pressure  at  all  or  a  very  low  one  below  it, 
piston  8  goes  down  instantly,  forcing  valve  10  away  from 
its  seat.  The  train  pipe  air  then  moves  check  15  up  and 
flows  through  C  into  brake  cylinder  till  pressures  equalize. 
When  these  valves  10  and  15  are  opened  in  this  manner, 
the  train  pipe  air  goes  past  them  like  a  flash  through  the 
large  ports  into  the  empty  brake  cylinder,  setting  the 
brake  with  the  pressure  at  which  the  train  pipe  and  brake 
cylinder  can  equalize,  which  is  somewhere  near  20  pounds. 
At  the  same  time  port  s,  in  the  end  of  slide  valve  3,  is 
open,  air  from  auxiliary  flows  through  r  and  piles  in  on 
top  of  train  pipe  air  in  cylinder,  raising  the  cylinder  pres- 
sure at  full  equalization  to  60  pounds.  The  train  pipe  air 
equalizes  first  with  cylinder,  through  large  ports,  and 
auxiliary  pressure  last,  through  small  ports.  Considerable 
air  passes  around  piston  8  which  is  not  an  air  tight  fit  in 
its  bushing. 


QUICK    ACTION    TRIPLE    VALVE  17 

Now  for  the  means  employed  to  let  the  auxiliary  reser- 
voir pressure  on  top  of  piston  8  at  one  time  to  produce 
"  quick  action  "  and  keep  it  out  at  another  to  preserve  the 
graduated  application.  As  long  as  this  triple  is  used  with 
a  graduated  application,  the  slide  valve  j  does  not  move 
over  far  enough  to  uncover  emergency  port  t,  as  with  a 
gradual  reduction  of  train  pipe  pressure  the  auxiliary  pres- 
sure will  be  reduced  equally  with  the  train  pipe  pressure 
through  the  graduating  valve  7  and  its  port  z.  The 
graduating  stem  21  and  its  spring  22  ordinarily  stop  the 
movement  of  the  piston  4  when  it  reaches  the  service 
application  position.  But  if  the  train  pipe  pressure  is 
reduced  so  suddenly  and  to  such  an  amount  that  the 
graduating  valve  can  not  reduce  auxiliary  pressure  equally 
with  train  pipe  reduction,  and  graduating  spring  does  not 
stop  the  piston,  the  greater  auxiliary  pressure  will  move 
piston  4  and  slide  valve  3  far  enough  so  port  t  will  be  un- 
covered, auxiliary  air  will  move  piston  8,  valves  10  and 
/5  will  move  at  once  and  "  quick  action "  is  the  result. 
The  Westinghouse  Co.  have  put  a  quick-action  triple 
valve  in  service  that  allows  train  pipe  air  to  flow  into  the 
brake  cylinder  during  a  service  application.  This  will  be 
described  later  on  in  this  book. 

A  sticky  triple  valve  or  any  defect  in  valve  7  that  will 
prevent  air  getting  past  it  will  sometimes  cause  the  quick 
action  operation  with  a  moderate  service  application  if  you 
have  a  short  train.  The  equalization  of  the  pressures  is 
the  foundation  principle  to  look  for  in  the  operation  of  the 
quick  action  triple. 

It  is  necessary  to  restrict  the  flow  of  air  through  some 
of  the  openings  in  triples  and  brake  valve  in  order  to  be 
sure  to  handle  a  long  train  with  safety.  This  refers  more 
particularly  to  the  "  feed  ports  "  in  the  triples  for  recharg- 
ing auxiliaries,  the  "  preliminary  exhaust  port "  h,  train 
pipe  exhaust  n  and  exhaust  ports  in  triple  valves.  The 
proper  size  of  these  ports  has  been  determined  by  the 
experience  of  many  years. 

Perhaps   it  would  be  well   to  study  on  the  matter  of 


l8  EQUALIZATION 

equalization  of  different  pressures  of  air  in  the  equipment, 
as  if  this  is  well  understood  you  can  solve  other  problems 
in  air  brake  operations  more  easily.  It  is  the  law  that 
where  compressed  air  in  a  certain  sized  vessel  expands  into 
an  empty  one,  the  pressure  is  reduced  in  the  full  one  in 
proportion  to  the  increased  volume  the  air  has  to  occupy. 
From  this  you  can  see  that  in  the  case  of  the  brake  cylin- 
der and  auxiliary  the  auxiliary  pressure  will  be  reduced 
more  if  the  brake  cylinder  is  large  in  proportion  to  the 
auxiliary  than  if  it  is  small.  Apply  this  law  to  the  cylin- 
ders having  different  piston  travels;  a  cylinder  having  a 
long  piston  travel  holds  a  greater  volume  of  air  than  the 
one  with  short  travel,  so  we  can  expect  the  one  with  long 
travel  to  reduce  the  auxiliary  pressure  to  a  lower  point 
than  the  short  travel,  and  it  is  found  that  a  travel  of  n 
inches  of  the  freight  brake  piston  gives  a  final  equalized 
pressure  of  close  to  45  pounds,  while  a  short  travel  of  4 
inches  gives  a  final  pressure  of  57  pounds;  a  travel  of  8 
inches,  which  is  between  4  and  II  inches,  will  give  a  final 
equalization  of  about  50  pounds.  The  difference  of  pres- 
sures with  long  and  short  piston  travels  is  more  marked 
with  partial  applications  than  with  full  equalization.  A 
5  pound  reduction  of  auxiliary  pressure  will  give  about  18 
pounds  per  inch  on  a  piston  with  4  inches  travel ;  while 
with  the  II  inch  travel  piston,  the  pressure  will  not  show 
anything.  This  will  give  different  brake  powers  on  dif- 
ferent cars  in  the  train,  although  it  should  be  equally  pro- 
portioned to  the  weights  of  the  cars;  unequal  brake  power 
makes  some  cars  hold  less  than  others,  so  the  strain  is  not 
equally  distributed  throughout  the  train,  a  point  in  equal- 
ization worth  studying  on. 

The  final  point  at  which  auxiliaries  and  their  cylinders 
equalize  cuts  quite  a  figure  in  operating  the  triples  to 
release  the  brakes.  A  variation  in  piston  travel  of  the 
different  brakes  changes  this  point  of  final  equalization  and 
will  be  explained  later.  As  was  stated  in  explaining  the 
operation  of  the  triple  piston,  the  train  pipe  pressure  must 
be  greater  than  the  auxiliary  pressure  to  move  the  triple 


EQUALIZATION  IQ 

piston  up  so  slide  valve  will  open  exhaust  port  and  let  air 
in  brake  cylinder  equalize  with  the  atmosphere;  then  the 
brake  piston  will  have  no  air  pressure  on  either  side  of  it. 
This  relieves  the  strain  on  brake  levers  and  shoes. 

If  auxiliary  pressures  on  this  final  equalization  are 
unequal  and  train  pipe  pressure  is  not  raised  at  once 
higher  than  the  highest  auxiliary  pressure,  all  the  brakes 
will  not  release  at  once.  This  leads  us  to  consider  the 
question  of  equalization  of  the  train  pipe  and  main  reser- 
voir pressures  when  you  desire  to  release  the  brakes. 

If  the  train  pipe  is  long  it  will  take  more  air  from  main 
reservoir  to  equalize  at  a  certain  stated  pressure  than  if  it 
is  short,  for  a  long  train  pipe  holds  more  air  than  a  short 
one.  Then,  again,  if  the  train  pipe  has  considerable  com- 
pressed air  left  in  it  after  setting  the  brake,  it  will  equalize 
at  a  higher  point  than  if  it  is  empty.  This  emphasizes  the 
fact  that  it  will  be  hard  work  to  release  the  brakes  on  a 
long  train  if  you  exhaust  all  the  air  in  making  an  applica- 
tion. 

Another  place  where  equalization  is  important  is  on  the 
second  application  shortly  after  releasing  brakes.  It  takes 
time  for  the  train  pipe  and  auxiliary  pressures  to  equalize. 
If  you  do  not  wait  this  proper  time  the  auxiliary  will  not 
have  charged  to  standard  pressure,  and,  of  course,  when 
brake  is  set  it  will  not  reach  as  high  a  final  pressure  on 
brake  piston,  which  reduces  the  braking  power. 

Equalization  between  train  pipe  and  auxiliary  on 
making  the  reduction  for  a  second  application  is  very 
important,  because  if  train  pipe  has  a  high  pressure  which 
the  auxiliary  has  not  reached,  the  triple  piston  cannot 
move  till  the  train  pipe  pressure  has  been  drawn  down  a 
trifle  lower  than  the  auxiliary.  If  one  is  80  and  the  other 
60,  it  means  a  reduction  of  20  pounds  before  brake  begins 
to  set,  and  about  20  more  to  set  all  brakes  tight.  This 
affects  the  work  of  the  brake  on  a  short  train  more  than  a 
long  one.  With  a  large  main  reservoir  and  a  short  train  it 
is  easily  done. 

This  defective  handling  of  the  brake  is  called  "  over- 


2O  BRAKE  OPERATION 

charging  the  train  pipe,"  and  can  be  avoided  by  returning 
the  brake  valve  to  lap  from  full  release  as  soon  as  the  train 
pipe  has  had  time  to  charge  up  its  whole  length,  which 
will  move  all  triples  to  exhaust  position  and  quickly 
equalize  the  train  pipe  and  auxiliary  pressures.  When 
these  pressures  are  equalized,  a  very  slight  reduction  in 
the  train  pipe  pressure  sets  all  the  triples  to  work  at  once. 
In  stopping  a  short  passenger  train  for  baggage  or  at  a 
water  plug,  if  the  stop  is  being  made  too  soon,  go  to  a  full 
release  for  an  instant  to  move  all  the  triples  to  release, 
then  back  to  service  application,  making  a  service  reduction 
of  6  or  8  pounds  which  will  probably  set  the  triples  before 
all  the  air  has  passed  out  of  brake  cylinders,  and  in  addition 
to  holding  the  brake  set  at  a  low  pressure  will  have  all  of 
them  ready  for  a  further  application  at  an  instant's  notice 
so  that  you  can  stop  at  the  exact  spot  required.  Never  try 
this  with  a  long  train  of  any  kind  at  slow  speed,  as  you  are 
liable  to  break  the  train  in  two. 

A  few  hints  on  getting  ready  to  make  a  good  stop  and 
knowing  whether  you  can  depend  on  the  brake  to  operate 
properly  may  be  of  service  here. 

When  operating  the  brake  valve,  you  should  listen  to 
the  sound  of  the  train  pipe  air  discharging  from  it,  because 
that  sound  tells  how  many  cars  you  have  in  your  train  with 
train  pipe  connected  and  how  the  valve  is  doing  its  work, 
just  as  the  exhaust  of  the  locomotive  tells  whether  the 
valve  motion  is  in  order ;  any  unusual  sound  notifies  you 
that  something  is  wrong. 

When  you  make  a  test  of  the  train  brake  before  starting 
out,  make  the  same  kind  of  an  application  as  when  stop- 
ping at  a  station,  by  successive  reductions ;  a  5  to  7  pound 
reduction  for  the  first  one,  lighter  ones  afterwards;  then 
you  will  know  how  the  brake  will  work  when  making 
station  stops.  It  should  be  full  application  to  get  the  full 
piston  travel. 

Never  make  an  emergency  application  when  testing 
brakes  unless  specially  called  for,  and  then  not  till  after  the 
first  test  has  been  finished. 


BRAKE  OPERATION  21 

If  the  brake  leverage  on  the  train  is  adjusted  for  70 
pounds  train  pressure,  it  is  not  safe  to  carry  either  more  or 
less.  If  you  carry  less,  you  cannot  top  quickly  when  you 
have  to;  if  you  carry  more  and  skid  the  wheels,  you  will 
slide  by  and  will  spoil  a  lot  of  wheels. 

Have  your  air  gage  properly  placed  and  well  lighted,  so 
that  it  can  be  seen  without  taking  your  eyes  too  far  off  the 
track  and  signals.  Consult  it  often  till  you  learn  the  air 
brake  business.  If  it  does  not  register  correctly  or  sticks 
when  the  pressure  is  changing,  call  the  attention  of  the 
proper  party  to  it. 

It  pays  to  inspect  and  test  your  engine  equipment  care- 
fully before  leaving  the  engine  house;  it  may  save  you  a 
failure  on  the  road. 

Drain  the  main  reservoir  daily;  the  tender  triple  should 
be  drained  regularly  in  cold  weather.  It  is  a  good  plan  to 
open  the  cocks  at  rear  of  tender  and  blow  out  the  train 
pipes  for  both  brake  and  signal  line  before  coupling  to 
the  train. 

Too  much  oil  used  in  the  air  end  of  the  pump  does 
more  harm  than  not  enough,  as  it  chokes  up  all  the  small 
openings  in  the  engine  equipment.  The  piston  rod  packing 
needs  more  oil  than  the  air  piston;  the  air  valves  do  not 
need  any. 

Use  good  valve  oil  always. 


WHEN   OPERATING  THE  AUTOMATIC   BRAKE 
REMEMBER 

That  the  compressed  air  stored  in  the  main  reservoir  is 
used  to  charge  up  the  train  line  and  auxiliary  reservoirs, 
and  that  it  is  used  to  release  the  brake.  Do  not  have  any 
water  in  any  reservoir,  as  it  takes  up  the  room  needed 
for  air. 

That  the  compressed  air  stored  in  auxiliary  reservoir  is 


22  BRAKE  OPERATION 

used  to  set  the  brake.  There  is  an  independent  supply  for 
each  brake.  Keep  a  full  supply  in  each  auxiliary. 

That  the  brake  is  set  by  any  reduction  of  pressure  in 
the  train  pipe,  no  matter  how  it  is  made,  if  it  is  sufficient 
to  move  the  triple  piston  and  valve. 

That  the  train  pipe  pressure  must  be  reduced  5  to  7 
pounds  at  first  application,  or  brake  pistons  will  not  travel 
over  leakage  grooves,  allowing  brake  to  leak  off. 

That  the  train  pipe  pressure  must  be  raised  above  the 
auxiliary  pressure,  or  the  auxiliary  pressure  reduced  by 
bleeding,  before  the  brake  will  release. 

That  you  cannot  recharge  an  auxiliary  reservoir  until 
the  exhaust  port  in  triple  is  wide  open,  unless  air  leaks 
past  triple  piston,  as  the  feed  port  does  not  open  until 
after  the  exhaust  port  is  open. 

That  a  second  application  after  release  does  not  set  the 
brake  as  tight  as  the  first  full  application,  unless  the 
auxiliaries  have  had  time  to  recharge  to  standard  pressure. 
This  takes  from  25  to  45  seconds. 

That  the  small  reservoir  attached  to  brake  valve  is  put 
there  to  give  a  larger  supply  of  air  for  the  preliminary 
exhaust  of  brake  valve  so  you  can  make  a  gradual 
reduction. 

That  if  your  driver  brake  does  not  work  quickly  and 
hold  well  with  service  application,  in  99  times  out  of  100 
it  is  on  account  of  a  leak. 

That  the  distributing  valve  used  with  the  locomotive 
brake  must  be  kept  clean  and  all  pipe  joints  tight  if  you 
expect  to  get  good  service  from  it. 

That  the  position  of  the  straight  air  brake  valve  and  the 
independent  brake  valve  has  all  to  do  with  the  application 
and  release  by  the  automatic  brake  valve  of  the  locomotive 
brake. 

That  in  all  these  questions  and  answers  it  is  understood, 
unless  otherwise  stated,  that  70  pounds  is  the  standard 
train  pipe  and  auxiliary  pressure ;  90  pounds  main  reservoir 
pressure;  and  8  inches  the  standard  piston  travel  for  all 
passenger,  freight  and  tender  brake  pistons.  The  brake 


DEFINITIONS  23 

piston  travels  an  inch  or  more  farther  when  train  is 
running  than  with  a  standing  test,  so  travel  should  be 
adjusted  to  less  than  8  inches. 

And  lastly,  we  will  define  some  of  the  terms  which  are 
used  to  shorten  the  explanations  you  may  hear. 

A  PARTIAL  application  means  that  the  brake  is  set  with 
part  of  its  full  force;  the  brake  cylinder  pressure  has  not 
equalized  with  the  auxiliary  reservoir  pressure. 

A  FULL  application  means  that  the  brake  cylinder  pres- 
sure has  equalized  with  the  auxiliary  pressure,  and  has, 
therefore,  got  the  full  pressure  that  can  be  obtained  from 
the  air  stored  in  the  auxiliary.  No  matter  how  many 
reductions  of  train  pipe  pressure  you  make,  it  is  only  one 
application  till  it  is  released.  You  can  reduce  the  train 
pipe  pressure  a  few  pounds  at  a  time  and  make  eight  or 
ten  successive  reductions,  but  it  is  only  one  application  if 
it  has  not  been  released. 

A  GRADUATED  or  SERVICE  application  means  a  gradual 
reduction  of  train  pipe  pressure  which  sets  the  brake 
slowly.  In  a  graduated  application  it  is  not  expected  that 
the  quick  action  parts  of  any  triple  valve  will  operate. 

An  EMERGENCY  application  means  a  sudden  and  heavy 
enough  reduction  of  train  pipe  pressure  to  set  the  brake 
with  full  force  at  the  first  movement  of  the  triple  valve. 
With  this  application  the  quick  action  part  of  the  triple 
valve  operates,  so  that  air  from  the  train  pipe  passes  into 
the  brake  cylinder  and  equalizes,  after  which  the  auxiliary 
and  cylinder  pressures  also  equalize. 


3S 


THE  8-INCH  AIR  PUMP. 

The  sectional  view  of  this  pump  shows  the  steam  and 
air  pistons  10  and  n  and  and  all  the  steam  valves  in  their 
positions  when  the  steam  piston  is  making  its  stroke  up- 
ward. 

The  live  steam  comes  from  the  boiler  through  the  gov- 
ernor and  passage  m  into  the  chamber  between  the  heads 
of  the  main  steam  valve  7.  It  also  goes  into  port  h  and 
through  a  passage  in  the  wall  of  the  steam  cylinder  and  in 
the  top  head,  which  is  not  shown  as  this  port  is  in  the  sec- 
tion cut  away.  This  passage  from  h  leads  live  steam  con- 
stantly into  the  steam  chest  e  of  the  reversing  valve  16;  it 
can  pass  through  port  a  into  the  cylinder  and  over  the 
reversing  piston  23,  pushing  it  down ;  for  the  combined  area 
of  the  piston  23  and  the  small  one  /  is  greater  than  that  of 
the  top  one  7.  This  opens  the  steam  port  in  the  bushing 
26 ;  steam  then  passes  under  steam  piston  10. 

At  the  same  time  the  exhaust  ports  in  bushing  25  are 
open  so  any  steam  in  the  top  end  of  the  cylinder  escapes 
at  y  through  f  and  g  to  the  exhaust  pipe.  This  moves  the 
steam  piston  up,  bringing  up  the  air  piston  //.  As  the  air 
piston  moves  up,  any  air  above  it  escapes  through  port  p 
by  raising  discharge  valve  30  and  passes  into  the  main 
reservoir.  At  the  same  time  the  lower  end  of  the  air 
cylinder  is  filled  with  air  from  the  atmosphere;  when  the 
piston  //  raises,  a  partial  vacuum  is  formed  under  it  and 
the  pressure  of  the  outside  air  forces  up  inlet  valve  33  and 
air  passes  into  cylinder.  On  the  arrival  of  the  piston  at  the 
top  of  its  stroke,  both  these  air  valves,  30  and  33,  drop  into 
their  seats,  remaining  there  during  the  return  or  down 
stroke.  The  other  set  of  air  valves  open  on  the  down 
stroke,  31  to  admit  air  above  the  piston  32  to  discharge 
air  from  the  lower  end  of  the  air  cylinder  to  the  main 
reservoir, 


26  THE  AIR  PUMP 

When  the  steam  piston  reaches  the  top  of  its  stroke,  the 
reversing  plate  18  strikes  the  shoulder  n  of  the  reversing 
rod  /7,  moving  it  up;  this  in  turn  moves  the  reversing 
valve  16  up  also.  Reversing  valve  16  being  moved  up  in 
chamber  e  covers  port  a  so  live  steam  can  no  longer  pass 
on  top  of  reversing  piston  23;  ports  b  and  c  are  connected 
by  the  cavity  in  valve  16  so  that  the  steam  in  cavity  d  over 
piston  23  exhausts  through  c  and  balances  the  pressure 
on  each  side  of  piston  23.  The  top  piston  of  main  steam 
valve  7,  which  has  live  steam  under  it,  being  larger  than 
the  bottom  one  and  piston  23  being  balanced,  the  main 
steam  valve  7  is  raised  up,  also  moving  up  23 ;  this  move- 
ment of  7  opens  the  upper  steam  ports  and  the  lower  ex- 
haust ports  to  that  live  steam  pushes  the  piston  10  down  to 
the  bottom  of  the  cylinder.  When  the  piston  reaches  the 
bottom  of  the  stroke,  the  reversing  plate  18  catches  on  the 
button  x  at  the  bottom  end  of  reversing  rod  17  and  moves 
the  reversing  valve  back  to  the  position  shown  in  the  cut ; 
'the  live  steam  then  moves  the  piston  valves  23  and  7  to  the 
positions  shown  there,  and  the  pump  is  ready  for  the  up 
stroke. 

The  first  sectional  view  of  the  p^-inch  pump  is  shown 
with  the  main  piston  65  and  all  the  valves  in  the  steam 
end  as  they  stand  when  the  pump  is  making  the  upward 
stroke.  The  live  steam  which  comes  up  through  passage 
a  at  the  back  of  the  pump  into  steam  chest  A  is  always  on 
top  of  the  main  slide  valve  83.  This  valve  is  shown  at  the 
right  hand  end  of  its  stroke,  in  which  position  it  uncovers 
port  b  so  steam  can  pass  down  to  the  bottom  end  of  steam 
cylinder  under  the  piston  65  and  push  it  upward.  At  the 
same  time  the  exhaust  cavity  of  this  slide  valve  83  connects 
the  port  r,  which  opens  into  the  top  end  of  the  steam  cylin- 
der, with  exhaust  port  d,  which  passes  down  around  the 
back  of  cylinder  to  the  exhaust  pipe;  the  steam  above  the 
piston  can  then  pass  into  the  exhaust.  This  slide  valve 
83  is  moved  by  the  differential  piston  valve  76,  with  the 
large  piston  77  on  one  end  and  the  small  piston  79  on  the 
other.  Chamber  E  is  always  connected  to  the  exhaust 


28  THE    9J^-INCH    AIR   PUMP 

passage  through  port  t  in  the  side  of  the  main  valve  bush- 
ing 75  so  that  this  piston  has  live  steam  on  the  steam  chest 
side  and  the  exhaust  on  the  other  at  all  times.  The  large 
piston  77  on  this  valve  76  has  live  steam  on  the  steam 
chest  side  and  the  office  of  the  reversing  valve  72  is  to  con- 
nect the  chamber  D  at  the  outside  end  of  77  with  the  live 
steam  or  with  the  exhaust  as  may  be  required  to  move  76 
back  and  forth.  When  D  is  connected  with  the  exhaust 
both  outside  ends  of  the  piston  valve  76  have  no  pressure 
on  them,  the  live  steam  between  the  heads  moves  77, 
which  has  the  greatest  area,  away  from  the  live  steam 
pressure  towards  the  right.  When  the  main  steam  piston 
65  approaches  the  top  of  its  stroke  the  reversing  plate  69 
strikes  the  shoulder  /  of  the  reversing  rod  71  which  is 
moved  up  carrying  the  reversing  valve  72  up ;  this  admits 
steam  into  port  g,  it  passes  along  the  side  of  the  bushing 
through  the  port  shown  into  chamber  D  at  the  outside  of 
piston  77,  which  having  live  steam  on  both  sides  of  it  is 
balanced.  Piston  79  has  live  steam  inside  and  exhaust 
outside,  so  it  moves  away  from  the  live  steam  drawing  the 
main  slide  valve  83  with  it.  This  movement  uncovers  port 
c,  live  steam  passes  down  on  top  of  the  piston  65,  the 
exhaust  cavity  of  83  connects  port  b  and  exhaust  port  d 
together  and  the  steam  from  bottom  end  of  cylinder  can 
pass  up  through  passage  or  port  b  to  the  exhaust  pipe. 
Steam  piston  65  will  then  make  the  down  stroke.  The 
position  of  all  the  valves  and  pistons  while  the  down  stroke 
is  being  made  is  shown  on  next  page.  When  close  to  the 
bottom  end  of  the  stroke,  the  reversing  plate  69  catches 
the  button  x  on  the  bottom  end  of  reversing  rod  71,  pulls 
this  rod  down  and  with  it  reversing  valve  7^,  and  connects 
chamber  D  with  the  exhaust  through  ports  f  and  h  in  the 
side  of  bushing  75.  As  soon  as  the  pressure  is  relieved, 
live  steam  moves 'piston  77  to  the  right,  drawing  the  main 
slide  valve  83  with  it;  all  steam  valves  are  then  in  the 
position  shown  on  page  26,  and  the  pump  begins  the 
upward  stroke.  The  main  valve  7  of  the  8-inch  pump  has 
live  steam  between  its  two  heads  or  pistons  at  the  same 


W8 

83 


88 
1O4 


88 


30  AIR    PUMP    CAPACITY 

time,  and  this  tends  to  force  the  main  valve  up.  Piston  23 
is  used  to  overcome  the  advantage  the  large  piston  7  has 
and  force  it  down  for  the  up  stroke  of  the  piston  10.  With 
the  9^-inch  pump  the  differential  piston  76  is  moved  by 
changing  the  pressure  on  the  outside  of  piston  77;  this  is 
done  by  the  reversing  valve  72.  The  angling  hole  in  cap 
nuts  20  and  74  serves  the  same  purpose  in  both  pumps — to 
balance  the  pressure  on  both  ends  of  the  reversing  rods — ; 
this  opening  connects  with  the  top  end  of  steam  cylinder, 
down  past  the  reversing  valve  bushing.  The  reversing 
valve  72  in  the  9^-inch  pump  performs  the  same  office  as 
valve  16  in  the  8-inch  pump,  but  the  reversing  valve  16 
admits  steam  over  the  top  of  16  through  port  a  to  piston  23, 
while  valve  72  admits  steam  under  the  bottom  end  through 
port  g  to  piston  77.  In  both  pumps  the  reversing  rods 
work  the  same  and  have  the  same  class  of  troubles.  The 
arrangement  of  the  steam  valves  in  the  9^-inch  pump  is 
much  superior  to  that  of  the  8-inch  in  every  way,  and  in 
addition  they  are  all  located  in  the  top  head  60.  In  case 
the  steam  valves  get  out  of  order,  by  changing  the  steam 
head  60  with  its  reversing  rod  71,  we  get  a  good  pump 
again. 

The  air  valves  in  the  9^2-inch  pump  are  all  of  one  size 
and  have  the  same  lift — three  thirty-seconds  of  an  inch ; 
when  new  they  are  interchangeable  with  each  other.  The 
air  valve  cages  88  are  also  interchangeable.  As  these  air 
valves  act  the  same  as  those  of  the  8-inch  pump  when  the 
pump  is  working,  an  explanation  is  not  necessary. 

This  pump  is  g}/2  inches  bore  and  10  inches  stroke ;  with 
140  pounds  of  steam  it  should  fill  a  main  reservoir  26^2 
inches  in  diameter  by  34  inches  long,  having  a  capacity  of 
about  15,000  cubic  inches,  from  o  up  to  70  pounds  in  38 
seconds,  or  from  20  to  70  pounds  in  27  seconds.  You  can 
determine  whether  a  pj^-inch  pump  is  in  good  order  by 
testing  it  and  noting  whether  it  can  do  this  work. 

An  8-inch  pump  should  pump  this  amount  of  air  from 
o  to  70  pounds  in  68  seconds,  and  from  20  to  70  pounds  in 
about  50  seconds,  using  steam  at  140  pounds. 


AIR    PUMP    CAPACITY  31 

The  n-inch  pump  is  much  the  same  in  construction  as 
the  9^2-inch  pump.  It  is  II  inches  bore  and  12  inches 
stroke.  The  air  valves  are  much  larger  but  have  the  same 
lift,  three  thirty-seconds  of  an  inch.  Its  operation  is  the 
same,  so  the  explanation  for  one  pump  will  do  for  the 
other.  The  capacity  is  much  greater,  as  100  strokes  of  the 
n-inch  pump  will  compress  48  cubic  feet  of  free  air,  while 
100  strokes  of  the  p^-inch  pump  will  compress  36  cubic 
feet.  When  working  at  full  capacity  the  n-inch  pump 
will  compress  58  cubic  feet  of  free  air  per  minute  and  the 
9^2-inch  pump  38  cubic  feet. 


DEFECTS  OF  THE  AIR  PUMP. 

Many  of  the  break-downs  and  defects  of  the  air  pump 
can  not  be  remedied  when  away  from  the  shop,  some  of 
them  can;  it  is  important  to  locate  the  nature  of  the  defect 
at  once  to  know  if  it  can  be  fixed  then  and  there,  or  if 
another  air  brake  engine  will  be  needed  to  handle  the  train. 

In  the  case  of  any  disability  or  break  down  of  the  steam 
end  the  pump  usually  stops  altogether.  If  the  air  end  is 
out  of  order  it  will  not  make  any  air  or  at. the  best  will 
work  irregularly.  We  will  first  take  up  the  disabilities 
which  will  make  the  8-inch  pump  stop  altogether.  First 
see  that  a  full  supply  of  steam  goes  to  the  pump ;  if  it  does 
not  the  trouble  may  be  in  the  governor. 

Leaky  gaskets  in  the  steam  head  or  leaks  past  the 
bushings  from  one  port  to  another  will  let  the  live  steam 
blow  into  the  exhaust  so  there  is  not  enough  pressure  to 
reverse  the  pump.  In  such  cases  you  can  hear  the  blow, 
the  pump  is  pretty  certain  to  stop  at  the  bottom  end  of  the 
stroke  and  stay  there.  If  the  copper  gasket  gets  cracked 
at  the  opening  where  steam  goes  through  from  port  h  into 
the  steam  head  the  live  steam  can  blow  on  one  side  into 
the  exhaust,  on  the  other  into  the  steam  cylinder;  this 
leak  does  not  always  stop  the  pump,  usually  it  does.  If 
anything  works  into  this  port  h  and  stops  it  up  so  steam 


100 


MAIN  VALVE  BUSHING 


This  cut  shows 
the  position  of  re- 
versing: valve  72 
when  pump  i  s 
making  the  up 
stroke. 

Port  s  in  main 
valve  bushing  is 
for  live  steam  to 
piston  77:  A  is  port 
for  exhaust -from 
this  piston ;  /con- 
nects with  exhaust 
portrf. 


This  cut  shows 
the  position  of  re- 
versing: valve  72 
when  pump  is 
making:  the  down 
-H  stroke. 

See  pag:e  28. 


OF  THE  AIR  PUMP  33 

can  not  pass  through  in  sufficient  volume  to  hold  proper 
pressure  for  the  reversing  piston  it  will  stop. 

Leaks  past  the  bushings  are  not  unusual ;  when  once 
they  start,  the  steam  soon  finds  a  way  to  get  to  the  exhaust 
without  doing  its  work. 

When  the  packing  rings  and  valves  in  the  steam  end 
become  worn  the  oil  will  blow  into  the  exhaust  before  it 
has  oiled  all  the  moving  parts.  This  will  leave  reversing 
piston  23  so  dry  that  it  will  not  move  and  reverse  the 
position  of  main  steam  valve  7.  This  is  a  case  where 
increasing  the  feed  of  oil  and  jarring  the  steam  head  with 
a  block  of  wood  will  usually  start  the  pump. 

A  piston  rod  broken  where  it  joins  piston  23  will  act 
much  the  same  way;  this  rod  has  been  known  to  get  stuck 
in  the  bottom  hole  in  the  bushing  and  hold  the  piston 
down.  The  small  hole  starting  in  the  side  of  this  bushing 
running  down  and  to  the  side  of  this  piston  rod  is  to  oil 
this  rod;  if  it  gets  stopped  up  it  should  be  opened.  Some- 
times the  top  of  reversing  piston  23  will  wear  to  a  steam 
tight  fit  against  the  cap  nut  21 ;  this  keeps  the  steam  off 
the  top  of  piston  23,  it  can  not  then  push  it  and  main  steam 
valve  7  down.  An  examination  of  these  surfaces,  and  if 
necessary  nicking  the  smooth  surfaces  so  the  steam  can 
get  in,  will  remedy  this. 

When  the  reversing  plate  18  gets  loose,  or  the  button  x 
on  the  reversing  valve  rod  17  breaks  off,  the  pump  will 
reverse  at  the  top  end  of  its  stroke  but  not  at  the  bottom 
and  will  stop  *at  the  bottom  end  of  its  stroke.  If  the  steam 
is  now  shut  off  and  the  reversing  valve  allowed  to  settle 
down  by  gravity  when  the  steam  is  turned  on,  the  pump 
will  make  another  double  stroke  and  stop  again.  Taking 
off  the  cap  nut  20  and  raising  up  the  reversing  rod  will 
show  whether  this  is  the  trouble.  In  this  case  a  spare  rod 
17  comes  handy.  If  the  plate  18  is  loose  the  steam  head 
will  have  to  come  off  to  get  at  the  plate.  If  one  of  the 
nuts  58  holding  the  air  piston  on  the  piston  rod  works  off, 
or  a  piece  of  it  breaks  off — these  nuts  split  sometimes — and 
gets  under  the  air  piston  so  that  it  can  not  come  clear 


34  AIR    PUMP    DEFECTS 

down  to  move  the  reversing  rod  and  valve  properly,  that 
will  stop  the  pump.  Take  out  the  plug  59  in  the  bottom 
head  of  the  air  cylinder  or  the  entire  head,  and  this  trouble 
can  be  located.  If  the  nuts  work  off  either  end  of  main 
steam  valve  7  the  pump  is  liable  to  stop  at  once.  If  the 
stop  pin  50  below  the  small  piston  7  breaks  off  so  the  small 
piston  gets  below  the  bushing  26  and  sticks,  the  pump 
will  stop  until  this  valve  can  be  moved  up. 

Stoppage  of  the  pump  may  be  caused  by  an  obstruc- 
tion working  into  some  of  the  small  steam  ports,  closing 
them  up,  especially  port  h.  Taking  off  the  cap  nut  21 
after  steam  has  been  shut  off  and  all  the  valves  settled 
down  will  locate  this  difficulty,  as  when  all  the  passages 
are  free  the  steam  will  come  out  through  port  a  over  the 
reversing  piston  23.  This  same  test  will  show  whether 
governor  is  open  for  steam  but  is  not  as  reliable  as  break- 
ing the  joint  between  the  governor  and  pump.  We  will 
speak  of  the  governor  later  on. 

As  the  reversing  rods,  plates  and  valves  are  of  the 
same  pattern  in  the  n-inch,  8-inch  and  Q^-inch  pumps, 
the  failures  of  any  of  these  parts  affect  all  these  pumps 
alike.  With  this  exception  the  steam  end  of  the  p^-inch 
pump  gives  very  little  trouble  if  the  joints  and  gaskets  are 
in  good  order. 

Nearly  all  the  blows  of  steam  when  the  pump  is  at 
work  take  place  when  the  steam  piston  is  making  the  up- 
ward stroke.  At  that  time  the  steam  can  blow  past  the 
steam  piston  packing  rings  for  when  on  the  down  stroke 
the  condensed  water  laying  on  top  of  this  piston  will  pre- 
vent much  steam  getting  by  the  rings ;  on  the  up  stroke 
there  is  nothing  of  the  kind  to  hold  the  steam  back.  On 
the  up  stroke  live  steam  is  on  top  of  reversing  piston  23  so 
it  can  blow  into  the  exhaust,  on  the  down  stroke  it  is  ex- 
haust on  both  sides.  With  the  differential  piston  76  of  the 
9^-inch  exhaust  steam  is  on  both  ends  on  up  stroke. 

A  blow  past  these  main  valves  of  either  pump  is  so 
nearly  like  a  blow  past  the  steam  piston  that  an  examina- 
tion is  necessary  to  determine  its  location.  A  bad  blow 
coming  all  at  once  is  a  good  indication  of  a  broken 


AIR    PUMP    DEFECTS  35 

packing  ring  or  a  leak  started  through  one  of  the  copper 
gaskets. 

II  the  top  end  of  the  reversing  rod  is  not  a  steam  tight 
fit  in  its  cap  nut  20  in  the  8-inch  or  74  in  the  9^  and  n-mch 
pump,  steam  will  blow  past  there  steadily  on  the  up  stroke ; 
passing  through  the  small  hole  drilled  obliquely  through  the 
cap  nut,  then  down  pait  the  reversing  valve  bushing  and  in- 
to the  upper  end  of  steam  cylinder  which  on  the  up  stroke 
is  connected  to  the  exhaust.  It  can  not  blow  on  the  down 
stroke,  as  at  that  time  live  steam  is  in  the  top  end  of  cyl- 
inder. Very  few  of  these  reversing  rods  are  steam  tight  in 
the  cap  nuts.  This  opening  between  the  steam  space 
above  the  piston  and  top  of  cap  nut  is  necessary  to 
balance  the  pressures  on  the  reversing  rod  so  it  will  not 
move  while  the  pump  is  making  its  stroke. 

If  the  reversing  rod  gets  bent  so  it  catches  on  the 
reversing  plate  or  the  button  catches  on  the  side  of  the 
hole  in  the  piston  rod,  the  pump  will  reverse  before  it 
completes  its  stroke.  A  pump  that  reverses  too  soon  in  its 
stroke  will  pump  very  little  air  into  the  main  reservoir. 

A  difficulty  in  the  air  end  of  the  pump  will  usually  give 
notice  at  once  by  a  quick  stroke  one  way  and  a  slow  stroke 
the  other,  which  may  be  caused  by  several  defects.  If  air 
from  main  reservoir  leaks  past  a  discharge  valve  it  will  fill 
that  end  of  the  cylinder  with  high  pressure  air  so  the  air 
piston  will  move  away  from  it  quickly  and  towards  it 
slowly.  In  such  a  case  the  inlet  valve  cannot  lift — no  air 
will  be  drawn  in  at  that  end.  If  the  inlet  valve  leaks  an 
examination  will  disclose  it  with  the  8-inch  pump.  With 
the  9^2  and  n-inch  pumps  it  is  not  so  easy,  as  the  air  pass- 
ing out  of  one  inlet  valve  will  pass  to  the  other  and  give  it 
the  signs  of  a  poor  suction  there.  Improper  lift  of  valves 
will  make  a  pump  move  faster  one  way  than  the  other.  If 
the  lift  of  an  inlet  valve  is  too  small,  that  end  of  the  cyl- 
inder may  not  fill  with  air  so  the  piston  will  not  meet  with 
so  much  resistance  in  compressing  the  air.  If  the  lift  of  a 
delivery  valve  is  too  small  the  piston  will  move  very  slowly 
at  the  last  part  of  the  stroke;  it  has  to  wait  for  the  com- 
pressed air  to  pass  through  the  small  discharge  opening. 


36  LEAKY    AIR    VALVES 

It  will  show  more  difference  in  relative  speed  when  the  air 
pressure  is  low. 

The  lift  of  the  receiving  valves  31  and  33  of  the  8-inch 
pump  should  be  one-eighth  of  an  inch,  of  the  discharge 
valves  30  and  32  three  thirty-seconds  of  an  inch.  This  lift 
is  very  soon  changed  by  the  wear  of  the  valves  and  the 
seats;  too  much  lift  of  discharge  valves  will  make  the 
pump  pound,  as  well  as  wasting  main  reservoir  air  by  al- 
lowing some  of  it  to  flow  back  into  the  cylinder  before 
the  valves  can  seat.  To  test  for  a  leak  in  the  bottom  dis- 
charge valve,  pump  up  full  pressure,  stop  the  pump,  take 
out  the  plug  in  the  bottom  head — air  will  blow  ot't  there 
steadily  from  a  leak.  To  test  for  a  leak  in  top  discharge 
valve  leave  this  bottom  plug  out  and  open  the  oil  cup  on 
top  end  of  cylinder;  see  if  air  blows  out  there  steady;  if 
so,  it  comes  from,  top  valve.  You  should  have  both  ends 
open  as  the  air  might  leak  past  piston  packing  and  appeal 
to  come  from  the  wrong  end. 

Leaky  packing  rings,  leaky  valves,  choked  air  passages, 
all  tend  to  make  the  pump  run  hot.  Running  the  pump 
at  too  high  a  speed  is  generally  the  trouble  in  the  first 
instance.  When  once  it  has  been  very  hot  the  packing 
rings  contract  and  do  not  fill  the  cylinder;  the  valve 
bushings  leak  and  the  oil  burns  on  the  inside  of  passages 
and  make  a  bad  matter  worse. 

The  Westinghouse  Company  are  now  making  a  cross- 
compound  air  pump  in  which  the  high  pressure  steam 
piston  operates  the  low  pressure  air  piston ;  the  steam  when 
exhausted  from  this  cylinder  then  passes  across  to  the 
other  end  of  the  low  pressure  steam  cylinder  and  operates 
the  low  pressure  steam  piston  and  the  high  pressure  air 
piston.  A  diagrammatic  view  of  this  pump  is  shown;  as 
by  this  means  the  steam  and  air  passages  can  be  more 
clearly  traced.  The  reversing  rod  21  and  valve  22  are  op- 
erated by  the  reversing  plate  18  at  the  end  of  the  stroke 
of  the  high  pressure  steam  piston  7  in  the  same  maner  as 
the  9^2-inch  pump.  The  differential  pistons  26  and  28  and 
valve  72  performs  the  same  functions  as  the  pistons  and 
valve  in  the  9^-inch  pump,  except  that  there  are  addi- 


CROSS-COMPOUND    AIR    PUMP  37 

tional  ports  in  valve  72  so  as  to  distribute  the  steam  to 
two  cylinders.  Live  steam  comes  in  over  the  main  valve 
through  port  a,  passes  through  opening  k  and  port  g  under 
piston  7  forcing  it  up.  If  the  pump  has  made  a  complete 
stroke  of  both  pistons  the  exhaust  steam  from  above  piston 
7  passes  out  through  port  c  and  the  passage  h  in  the  valve 
down  into  the  top  end  of  the  low  pressure  cylinder  at  d, 
forcing  that  piston  down.  Exhaust  steam  from  the  lower 
side  of  piston  8  is  passing  out  through  port  f  and  exhaust 
cavity  i  to  the  final  exhaust  e  and  then  to  the  atmosphere. 
Port  n  is  the  live  steam  port  from  the  reversing  valve 
seat  to  the  end  of  piston  26  and  serves  the  same  purpose 
as  port  g  in  the  p^-inch  pump.  Port  m  is  the  exhaust 
port  from  the  chamber  at  the  outside  of  piston  26  and 
corresponds  to  port  h  in,  the  p^-inch  pump.  /  is  the  ex- 
haust port  from  the  reversing  valve  seat  and  corresponds 
to  ports  f  and  t  in  the  9^2  pump.  '  By  following  the 
arrows  shown  in  the  passages  a  good  idea  of  the  flow  of 
the  steam  can  be  learned.  With  this  pump  there  is  but  one 
set  of  valves  and  reversing  gear  in  the  steam  end  and 
that  connected  to  the  high  pressure  piston.  The  movements 
of  the  pistons  are  at  the  same  time,  but  in  opposite  direc- 
tions. The  high  pressure  steam  piston  7  moves  up,  its 
exhaust  steam  moves  the  low  pressure  steam  piston  8 
down  and  vice  versa.  Air  compressed  above  the  low  pressure 
air  piston  9  flows  past  intermediate  discharge  valve  39  and 
port  u  in  over  piston  10.  Free  air  enters  through  the  lower 
air  inlet  and  port  r  past  inlet  valve  38  and  then  into  the  low- 
er end  of  the  cylinder  as  piston  9  moves  up.  High  pressure 
air  piston  10  on  its  down  stroke  compresses  the  air  below 
it  out  at  port  v'  past  lower  discharge  valve  42  and  through 
passage  w  to  the  main  reservoir.  During  the  stroke  of  the 
pistons  the  intermediate  pressure,  being  that  between  the 
low  and  high  pressure  air  pistons,  reaches  about  40  pounds. 
On  the  opposite  strokes  of  these  pistons  free  air  comes  in 
at  inlet  valve  37,  the  intermediate  pressure  air  goes  out 
at  valve  40  and  high  pressure  air  past  discharge  valve  41. 
The  high  pressure  steam  piston  7  has  a  diameter  of  8^2 
inches,  the  low  pressure  steam  piston  8  is  14^2  inches. 


28 


78 


40  38 


DIAGRAM  OF  THE  CROSS  COMPOUND  PUMP 
UP-STROKE,  HIGH-PRESSURE-STEAM  SIDE 


THE  PUMP  GOVERNOR  39 

All  pistons  have  a  stroke  of  12  inches.  The  low  pressure  air 
piston  is  14^2  inches  and  the  high  pressure  air  piston  is  9 
inches  in  diameter.  The  capacity  of  this  pump  is  131 
cubic  feet  of  free  air  per  minute,  as  against  58  for  the 
1 1 -inch  pump  working  under  the  same  conditions. 

Cross-compound  pumps  are  now  being  built  of  a  smaller 
size  than  given  above,  to  correspond  in  capacity  to  the 
9^2  and  n-inch  pumps. 


THE  PUMP  GOVERNOR. 

The  duty  of  the  pump  governor  is  to  shut  off  the 
steam  from  the  air  pump  when  the  air  pressure  has  reached 
the  standard  desired.  Where  only  one  pressure  is  to  be 
controlled,  the  single  governor  is  used;  if  more  than  one 
pressure,  the  duplex  governor  is  used.  The  steam  valve 
and  its  air  piston  are  the  same  with  both  the  duplex  and 
single  governors,  but  one  or  two  air  tops  are  used,  accord- 
ing to  the  number  of  air  pressures  controlled. 

It  is  located  close  to  the  pump  on  the  steam  pipe,  at 
the  union  connection  70  the  air  that  operates  the  governor 
enters,  and  is  under  the  diaphram  67.  This  diaphram  is 
held  down  by  the  regulating  spring  66,  which  can  be  ad- 
justed by  the  regulating  nut  65. 

We  will  suppose  that  the  spring  66  has  been  adjusted  to 
hold  the  diaphram  down  against  the  air  pressure  of  90 
pounds  and  no  more.  When  the  air  pressure  exceeds  90 
pounds  the  diaphram  will  be  raised  against  the  resistance 
of  the  spring;  this  will  raise  the  air  valve,  air  will  flow  in 
on  top  of  the  air  piston  53  and  force  it  down,  moving  steam 
valve  down  to  its  seat  and  closing  the  steam  supply  to  the 
pump,  which  will  stop  it. 

As  soon  as  the  air  pressure  falls  so  the  regulating  spring 
66  can  move  the  diaphram  down  and  close  the  air  valve 
the  air  pressure  above  the  piston  drops,  and  the  steam 
valve  is  opened  allowing  the  pump  to  take  steam  again. 
With  the  duplex  governor  the  regulating  spring  of  one  air 
top  can  be  adjusted  for  one  pressure  and  the  other  spring 


PUMP   GOVERNOR  DEFECTS 


'  DETAILS. 


PUMP  GOVERNOR 
Pun  K« 


50.    Steam- Valve  Body. 
5J.    Steam  Valve. 
5-2.    Cylinder  Cap. 
Kt.    Governor  Pisto.. 
5«.     Piston  Packing  RingJ 
VY     Governor-Piston  Nut. 
50.  .  Go 

•57.    Strain.  Valvo  Cylindi 
6i^   Diaplirngm  Body. 

63.  Spring  Box. 

64.  Cap  Nut. 

65.  Regulating  Nut. 
C6.    Regulating  Spring, 
itf.    Diaphrag 

\68,    Diaphragi 


for  another  pressure.  Thus  the  pressure  carried  depends 
on  which  side  of  the  governor  is  in  operation. 

There  are  several  causes  which  will  prevent  the  gover- 
nor from  shutting  off  the  steam  from  the  pump  when  the 
maximum  air  pressure  is  obtained.  If  the  regulating 

spring  is  screwed  down  too 
tight  it  will  not  allow  the 
diaphram  to  raise  and  lift 
the  air  valve  off  its  seat.  If 
too  much  oil  is  used  in  air 
end  of  pump  the  air  valve 
gets  gummed  up  where  it 
rests  on  its  seat  so  air  can 
not  get  through  after  air 
valve  raises.  This  is  the 
most  common  cause  of  the 
pressure  gtetting  higher 
than  the  governor  is  set 
for.  To  cure  this  trouble 
take  out  diaphram  and 
clean  off  air  valve  and  its 
seat  so  air  can  get  through 
freely  when  air  valve  raises. 
If  the  air  leaks  past  piston 
as  fast  as  it  comes  through 
air  valve,  the  piston  will 
not  be  moved  down  as  there 
will  be  no  pressure  above 
piston.  Putting  in  a  tight 
packing  ring  cures  this  un- 
less the  cylinder  is  worn 

out  of  true.  If  the  governor  piston  sticks  so  air  pressure 
will  not  force  it  down,  steam  will  not  be  shut  off.  If  the 
waste  pipe  in  the  side  of  steam  end  of  governor  is  stopped 
up  so  steam  or  air  is  confined  below  piston,  the  governor 
will  not  shut  off  at  any  pressure.  This  waste  pipe  may 
be  smashed  out  flat  so  nothing  can  pass  through  it,  in  cold 
weather  it  will  freeze  solid  full  at  the  bottom  end  which 
will  keep  the  air  piston  held  up.  If  anything  gets  in  over 


PUMP   GOVERNOR   DEFECTS  4! 

diaphram  so  it  cannot  raise,  that  will  hold  air  valve  shut 
so  air  cannot  get  on  piston  to  shut  off  steam  valve.  If 
valves  and  seats  are  kept  clean,  and  all  parts  allowed  to 
move  as  they  should,  governor  will  work  accurately.  In 
case  the  governor  shuts  off  the  steam  with  less  than  the 
standard  pressure  you  are  likely  to  find  there  is  dirt  or  a 
scale  holding  the  air  valve  off  its  seat  so  air  can  get 
through  on  top  of  piston  steadily,  in  which  case  the  gov- 
ernor will  shut  off  steam  as  soon  as  air  pressure  on  the 
top  of  governor  piston  will  more  than  balance  steam  pres- 
sure on  steam  valve.  If  this  air  valve  seat  is  injured  so  it 
leaks,  or  a  new  valve  has  been  put  in  that  is  too  short  to 
make  a  good  joint,  a  very  low  air  pressure,  less  than  forty 
pounds,  will  shut  off  the  steam.  A  broken  regulating 
spring  will  also  do  this. 

Sometimes  the  pump  will  not  start  up  soon  after  the  air 
pressure  in  the  governor  has  been  reduced  below  that  the 
governor  diaphram  is  set  at.  This  is  because  when  the  air 
valve  closes,  the  air  is  shut  up  in  cylinder  over  governor 
piston  and  must  leak  out  before  piston  can  raise  and  open 
steam  valve.  The  old  type  of  governor  D-g  had  this  trouble' 
but  the  new  style  of  governor  E-8  has  a  small  blow  hole 
drilled  in  the  side  of  62,  below  air  valve  seat,  which 
lets  enough  air  escape  after  standard  pressure  is  reached 
to  keep  pump  running  steadily.  Another  way  is  to  cut  a 
small  crease  through  the  threads,  so  the  air  over  piston  will 
leak  out  in  about  two  seconds  and  let  pump  go  to  work. 
If  this  crease  gets  stopped  up  with  gum  it  should  be 
cleaned  out;  after  which  the  governor  should  let  the 
pump  go  to  work  promptly. 

To  find  if  the  trouble  is  in  the  governor  when  the 
pump  will  not  start,  open  both  drip  cocks  in  the  95/2-inch 
or  ii-inch  pumps,  or  break  the  joint  between  the  governor 
and  8-inch  pump;  if  live  steam  comes  out  freely  the  gov- 
ernor is  not  at  fault.  In  such  a  case  shut  off  steam  at  the 
boiler,  wait  a  few  seconds  till  steam  is  out  of  pump  and 
turn  it  on  again,  if  the  live  team  blows  out  freely,  the 
trouble  is  in  the  pump. 


PIPING  THE  GOVERNOR. 

With  the  single  top  governor  and  a  brake  valve  using  a 
feed  valve  to  regulate  the  train  pipe  pressure,  main  reser- 
voir air  is  used  to  operate  the  governor,  with  some  types 
of  brake  valves  like  the  old  D-8,  train  pipe  pressure  oper- 
ates the  governor.  With  the  duplex  governor  one  side  is 
usually  piped  to  the  main  reservoir  direct,  the  other  side, 
in  some  cases,  uses  train  pipe  air.  With  the  high  speed 
brake,  one  side  is  set  for  90  pounds,  the  main  reservoir 
pressure  used  with  the  ordinary  train  pipe  pressure  of  70 
pounds;  the  other  side  for  the  higher  pressure  needed  to 
release  brakes,  using  no  pounds.  In  such  cases  there  is  a 
stop  cock  in  the  90  pound  side  air  pipe,  which  is  to  be 
closed  to  cut  out  that  side  when  the  higher  pressure  is 
used. 

There  is  also  a  method  of  piping  which  allows  of  two 
main  reservoir  pressures  being  used,  one  on  release  and 
running  position  of  the  F-6  brake  valve  and  a  higher  one 
with  the  valve  on  lap  and  application  positions.  The  90 
pound  side  is  piped  to  the  port  f  in  the  1892  model  brake 
valve  at  a  point  just  above  the  figure  62 — see  the  cut  of 
this  valve  farther  on.  When  the  rotary  is  in  full  release 
or  running  position,  main  reservoir  air  can  come  freely 
into  this  port  and  operate  the  governor  at  a  pressure  of 
90  pounds.  During  a  brake  application  this  port  f  is  closed 
by  the  rotary  and  the  air  pressure  there  soon  equalizes 
with  the  train  pipe. 

The  90  pound  side  of  the  governor  does  not  then  con- 
trol the  pump  and  the  high  pressure  side  which  is  connected 
directly  to  the  main  reservoir  and  adjusted  for  a  pressure 
higher  than  90  pounds,  usually  no  pounds,  allows  the 
pump  to  run  and  raise  the  main  reservoir  pressure  so  as 
to  have  a  good  stiff  excess  to  release  brakes. 

There  is  also  a  method  of  piping  the  duplex  governor 
to  control  the  amount  of  excess  pressure  regardless  of 


PIPING    THE   EXCESS    GOVERNOR 


43 


what  the  train  pipe  pressure  may  be.  One  side  is  piped  to 
the  main  reservoir  direct  at  MR,  and  set  120  or  130  pounds, 
according  to  what  the  maximum  main  reservoir  pressure 
is  to  be.  The  other  side  has  a  light  spring  51  over  the 
diaphram  that  has  the  proper  tension  to  hold  the  diaphram 
52  down  for  the  excess  desired.  At  A  B  V  main  reservoir 
air  from  the  brake  valve  comes  in  under  the  diaphram  at  d. 
At  FVP  train  pipe  air  at  the  reduced  pressure  comes  in 
above  the  diaphram,  and  its  pressure  is  added  to  that  of 
the  spring  51,  so  that  we  have  70  pounds  train  pipe  plus 
that  of  the  spring — say  20  pounds — so  that  when  the  main 

reservoir  air  in  d  can 
overbalance  the  pres- 
sure of  70+20  above 
the  diaphram,  the  dia- 
phram will  raise  the 
pin  valve  and  admit 
air  over  the  governor 
piston  and  close  the 
steam  valve  26.  This 
will  operate  the  same 
at  any  other  train 
pipe  pressure ;  s  o 
there  will  be  the  same 
excess,  depending  on 
the  adjustment  of  the 
spring  51.  Air  passes 
in  at  ABV  only  in 
release,  running  and 
PUMP  GOVERNOR  holding  positions  of 

the  H-5  brake  valve.  When  the  brake  valve  is  moved  to 
lap  or  beyond  the  air  is  cut  off  from  under  the  diaphram 
at  d  and  the  pressure  at  a  and  spring  41  control  the  pump. 


AIR  BRAKE  CATECHISM. 

i.  Q.  what  are  the  essential  parts  of  the  automatic 
brake  and  what  service  does  each  part  perform? 

A.  The  air  pump,  the  main  reservoir,  the  engineer's 
brake  valve,  the  train  pipe  with  its  hose  and  couplings, 
the  auxiliary  reservoir,  the  triple  valve,  the  brake  cylinder, 
the  gage  and  the  pump  governor.  The  air  pump  com- 
presses the  air  for  setting  and  releasing  the  brake;  the 
main  reservoir  is  used  to  store  a  supply  of  air  for  charging 
the  train  pipe  and  auxiliary  reservoirs  when  empty,  as  well 
as  to  hold  the  supply  for  increasing  the  train  pipe  pressure 
when  the  brake  is  to  be  released  and  to  charge  the  train 
pipe  and  auxiliaries  ready  for  the  next  application;  the 
brake  valve  governs  the  passage  of  the  air  from  the  main 
reservoir  to  the  train  pipe,  from  the  train  pipe  to  the  atmos- 
phere, or  stops  the  flow  of  air  through  it  in  any  direction. 
The  brake  can  be  set  gradually  or  full  on,  held  set  or 
released,  when  this  valve  is  properly  handled  by  the 
engineer.  The  train  pipe,  with  its  hose  and  couplings, 
extends  from  the  brake  valve  and  supplies  each  auxiliary 
reservoir  with  air  for  setting  the  brake.  It  is  also  a  means 
of  communication  from  the  engineer's  brake  valve  to  each 
triple  valve,  and  from  one  triple  valve  to  another  in  the 
quick  action  or  emergency  application. 

Each  brake  has  an  auxiliary  reservoir  in  which  the  air 
is  stored  for  operating  it  to  set.  The  triple  valve  consists 
of  three  separate  valves  and  is  connected  to  the  train  pipe, 
auxiliary  and  brake  cylinder;  it  is  used  to  control  the 
charging  of  the  auxiliary  with  air  and  regulate  the  time  in 
which  this  is  done,  to  open  a  valve  to  admit  air  from 
auxiliary  to  brake  cylinder  to  set  the  brake,  or  by  another 
movement  to  close  this  valve  and  open  the  exhaust  port 
so  air  can  get  out  of  brake  cylinder  to  the  atmosphere  and 
release  the  brake.  Thus  the  functions  of  the  triple  valve 
are  three-fold,  Jo  charge  the  auxiliary,  set  the  brake  and 


INSPECTION  AT  ENGINE  HOUSE  45 

release  it.  The  triple  valve  is  operated  by  a  variation  of 
pressures  between  the  train  pipe  and  auxiliary;  this  varia- 
tion is  controlled  by  the  brake  valve.  The  brake  cylinder, 
with  its  piston  connected  to  the  brake  levers,  beams  and 
shoes,  sets  the  brake  when  the  triple  valve  lets  air  into  it. 
The  gage  shows  with  the  red  hand  the  main  reservoir 
pressure,  with  the  black  hand  the  pressure  in  the  brake 
valve  above  the  equalizing  piston  and  in  the  brake  valve 
reservoir;  when  brake  valve  is  in  full  release  or  running 
position  it  also  shows  the  train  pipe  pressure.  The  pump 
governor  is  located  in  the  steam  pipe  to  the  pump;  it  is 
operated  by  the  air  pressure  and  shuts  off  steam  from  the 
pump  when  the  air  pressure  reaches  the  standard  amount 
carried. 

In  addition  to  these  essential  parts  there  is  the  pressure 
retaining  valve  that  is  attached  to  the  exhaust  outlet  of 
the  triple  valve  and  controls  the  flow  of  air  away  from  the 
brake  cylinder  when  the  triple  valve  is  in  release  position ; 
the  conductor's  valve  that  when  opened  reduces  the  train 
pipe  pressure  and  applies  the  brake,  the  release  valve  or 
bleeder  connected  to  the  auxiliary  reservoir  used  to 
reduce  the  auxiliary  pressure  and  release  a  single  brake.  A 
separate  valve  and  its  reservoir  called  the  distributing 
valve  is  used  on  locomotives  and  performs  the  duties  of 
the  triple  valve  by  applying  and  releasing  the  locomotive 
brake.  A  high  speed  reducing  valve  is  used  on  coaches. 

2.  Q.  What  are  the  duties  of  an  engineer  as  to  his  air 
brake  equipment  when  leaving  the  roundhouse? 

A.  To  start  his  pump  slowly  and  increase  its  speed 
after  15  or  20  pounds  of  air  have  picked  up ;  to  be  sure 
that  pump  is  in  good  order  and  will  pump  a  full  supply 
of  air  promptly;  to  know  that  governor  shuts  off  the  pump 
when  the  proper  pressure  is  reached  and  allows  it  to  start 
promptly;  to  see  that  lubricator  has  oil  enough  in  it  for 
the  trip;  to  know  that  there  is  no  water  in  the  main  reser- 
voir, drain  cup,  triple  valves  or  auxiliary  reservoirs ;  to 
test  all  the  joints  in  piping,  also  brake  valve  and  triple 
valves  for  leaks,  and  have  leaks  made  tight;  to  see  that 


46  TESTING    FOR    LEAKS 

tender  and  driver  brake  pistons  have  the  proper  travel  and 
do  not  leak  off  when  set;  to  test  the  air  signal  if  one  is 
used. 

3.  Q.     Why  must  the  pump  be  started  slowly,  oil  used 
cautiously,  triple  valves,  reservoirs  and  tender  strainers  be 
drained,  and  how  often? 

A.  The  pump  must  be  started  slowly  to  allow  the 
condensed  water  to  get  out  of  steam  end,  and  run  slowly 
till  the  air  pressure  rises,  or  the  piston  will  strike  the 
heads  of  air  cylinder.  The  triple  valves,  reservoirs  and 
strainers,  or  drain  cups,  should  be  drained  every  day  in 
cold  weather,  once  a  week  in  warm  weather.  Oil  should 
be  used  sparingly  in  air  end  of  pump.  It  should  never  be 
put  in  through  the  air  inlets  of  the  pump,  as  it  soon 
collects  dirt  and  chokes  up  the  air  passages,  which  helps 
to  make  the  pump  run  hot. 

4.  Q.     How  do  you  test  for  leaks  in  the  engine  equip- 
ment ? 

A.  When  full  pressure  is  obtained — 70  in  train  line,  90 
in  main  reservoir — shut  off  pump,  place  valve  on  lap;  if 
red  hand  drops  and  black  hand  is  stationary,  it  is  a  sign 
of  a  leak  somewhere  in  main  reservoir  line,  which  begins  at 
valves  in  pump  and  ends  at  brake  valve.  It  may  be  in 
joints  of  piping,  in  main  reservoir  drip  plug,  in  the  air 
signal  line,  in  valves  of  pump  or  brake  valve.  If  there  is 
an  air  sander  or  air  bell  ringer  on  the  engine  their  valves 
are  liable  to  leak.  If  main  reservoir  pressure  falls  rapidly 
when  you  are  sure  it  is  not  going  into  train  pipe  under 
rotary,  examine  each  of  the  places  mentioned.  With  the 
use  of  the  cut-out  cock  under  brake  valve  a  leak  under 
rotary  is  soon  detected.  Set  the  brake  full  on,  place  the 
valve  on  lap,  shut  the  cut  out  cock ;  if  rotary  leaks  into 
train  pipe  the  black  hand  will  soon  show  same  pressure  red 
one  does;  if  rotary  is  tight  and  air  leaks  out  of  train  pipe 
the  black  hand  will  drop.  With  a  leak  in  train  pipe  of 
engine  or  tender  and  cut  out  cock  shut,  the  brake  will  set ; 
with  valve  on  lap  and  cut  out  cock  open  the  black  hand 
will  fall  slowly.  For  a  leak  in  signal  line  shut  the  cut 


TRAIN    PIPE    INSPECTION  47 

out  cock  next  the  reducing  valve;  a  leak  here  will  make 
the  whistle  blow.  Using  a  torch  or  putting  soapsuds  on 
a  suspected  leak  will  generally  locate  air  blowing  out 
there. 

5.  Q.     Why  must  there  be  no  leaks  in  your  train  pipes 
or  any  other  part  of  your  air  brake  supply? 

A.  If  train  pipe  leaks,  brake  will  continue  to  set  tighter 
when  brake  valve  is  put  on  lap,  and  stop  the  train  before 
you  want  it  to,  so  that  it  is  necessary  to  let  it  off  and  make 
another  application  for  an  ordinary  stop.  If  cars  are  cut 
off  from  engine,  they  must  be  bled  at  once  if  their  train 
pipe  or  angle  cocks  leak.  Train  pipes  sometimes  get  worn 
through  where  they  rest  on  or  rub  against  something,  so 
they  are  tight  when  standing  still  and  leak  when  moving 
or  shaken  around.  This  leak  sets  the  brake  when  train  is 
in  motion,  and  no  leak  can  be  heard  when  standing  still. 
Jar  the  pipes  a  little  when  inspecting  the  engine  to  locate 
this  leak.  Sometimes  the  brake  levers  strike  the  end  of 
plug  in  stop  cock  and  push  it  in  so  it  will  leak  when  brake 
is  applied. 

6.  Q.     Why  must  all  hose  couplings  be  hung  up  prop- 
erly when  not  in  use?    Why  should  they  always  be  blown 
out  at  rear  of  tender  before  uniting  to  other  couplings? 
What  is  the  difference  between  an  air  brake  and  an  air 
signal  coupling? 

A.  So  no  dirt  or  foreign  matter  will  get  into  the  open 
coupling  and  work  into  the  triple  or  brake  valve  or  stop 
up  strainers.  So  couplings  and  gaskets  will  not  get  injured 
or  broken  dragging  over  rails  and  crossings.  If  blown 
out  each  time,  any  water,  sand  or  dirt  in  the  tender  piping 
will  be  blown  out.  Air  brake  and  air  signal  couplings  are 
of  different  sizes — made  so  purposely — so  the  brake  line 
cannot  be  coupled  to  the  signal  line.  The  opening  and  lip 
of  the  lock  in  brake  coupling  is  much  wider  than  the  signal 
coupling,  so  the  brake  coupling  will  not  go  into  it.  It  is 
the  practice  to  paint  the  signal  couplings  red  so  they  are 
more  easily  distinguished  when  taking  hold  of  them  to 
couple  up. 


48  WATER    IN    MAIN    RESERVOIR 

7.  Q.     If  main  reservoir  has  water  in  it,  how  will  it 
affect  the  operation  of  the  brake? 

A.  The  water  in  main  reservoir  reduces  the  supply  of 
air  stored  there  in  proportion  to  the  amount  of  water  con- 
tained. The  brake  will  set  the  same,  but  on  a  long  train 
will  not  release  as  readily,  as  there  will  not  be  enough  air 
stored  to  recharge  the  train  line  quickly  and  you  must 
wait  to  have  it  pumped.  The  main  reservoir  should  be 
entirely  clear  of  water,  even  if  it  is  necessary  to  drain  it 
each  trip,  so  as  to  get  a  prompt  release  and  recharging 
of  train. 

8.  Q.    How  does  this  water  get  into  the  main  reser- 
voir? 

A.  The  air  from  the  atmosphere  before  compression 
contains  more  or  less  moisture  in  the  shape  of  vapor. 
After  compression  the  air  can  not  hold  all  this  vapor  as  it 
is  compressed  to  a  very  much  smaller  volume,  so  nearly  all 
the  vapor  falls  to  the  bottom  of  the  main  reservoir  as  solid 
water  as  soon  as  the  air  cools  off  to  the  normal  temperature 
of  the  outside  air.  If  the  pump  runs  hot  so  the  air  does 
not  cool  off  in  the  main  reservoir  some  of  the  water  will 
be  found  in  the  triple  valves  and  drain  cups. 

9.  Q.     Of  what  use  is  the  extra  main  reservoir  pres- 
sure, and  does  the  size  of  the  reservoir  have  anything  to 
do  with  the  amount  of  excess  pressure  you  carry? 

A.  It  recharges  the  train  pipe  and  forces  the  triple 
pistons  up  into  exhaust  position  quicker  and  surer,  so  that 
all  brakes  release  about  the  same  instant;  recharges  the 
auxiliary  to  full  pressure  in  less  time,  ready  for  the  next 
application.  With  a  large  main  reservoir  there  is  a  greater 
volume  of  compressed  air  stored  to  draw  from,  so  a  less 
number  of  pounds  of  excess  pressure  will  do  the  work  than 
with  a  small  reservoir.  With  a  short  train  good  work  can 
be  done  with  less  excess  than  on  a  long  train.  Excess 
pressure,  as  well  a  a  large  volume  of  stored  air,  is  needed 
on  a  long  train,  so  the  air  will  travel  from  the  engine  to  the 
rear  car  more  quickly  and  release  the  rear  brakes  at  nearly 
the  same  instant  the  front  ones  release;  this  will  avoid 


EXCESS  PRESSURE  49 

many  break-in-twos.  Excess  is  needed  to  release  brakes 
and  large  volume  to  hold  up  the  pressure  in  train  pipe  for 
recharging.  The  main  reservoir  should  always  be  drained 
of  water  so  it  will  be  full  sized. 

10.  Q.     Could   it   release   the   brakes    with    an   empty 
train  pipe  as  readily  as  when  the  pressure  in  the  train  pipe 
had  been  reduced  only  20  or  25  pounds?    Why? 

A.  No.  When  the  air  from  the  main  reservoir  expands 
into  an  empty  train  pipe,  it  will  not  fill  it  up  and  equalize 
at  as  high  a  pressure  as  when  the  train  pipe  has  some 
compressed  air  left  .in  it.  For  instance,  the  train  pipe  line 
of  25  freight  cars  holds  16,000  cubic  inches,  about  as  many 
cubic  inches  of  air  as  an  ordinary  main  reservoir.  If  this 
train  pipe  is  entirely  empty  and  the  main  reservoir  has  90 
pounds,  it  will  equalize  into  twice  the  space,  and  show 
half  the  pressure,  or  45  pounds  in  each.  The  brake  would 
be  set  at  50  pounds ;  with  that  pressure  above  triple  piston, 
brakes  could  not  release  until  the  pump  had  raised  the 
pressure  over  five  pounds.  Now,  if  the  train  line  has  been 
reduced  25  pounds,  having  45  pounds  still  left  in  it,  90  in 
main  reservoir  and  45  in  train  pipe,  would  equalize  at  a 
little  over  65,  which  wpuld  raise  triple  pistons  so  brakes 
would  release  promptly. 

11.  Q.    Would  you  run  your  pump  as  fast  to  recharge 
an  empty  train  pipe  as  one  with  45  or  50  pounds  in  it?    Is 
there  any  economy  in  retaining  as  much  air  as  possible 
and  keeping  the  pump  cool? 

A.  The  pump  would  have  to  run  faster  to  recharge  an 
empty  train  pipe  than  one  with  45  or  50  pounds  in  it. 
When  you  empty  the  train  pipe  of  25  cars  it  wastes  as 
much  air  as  when  you  empty  a  small  main  reservoir; 
smaller  trains  in  proportion.  This  would  make  some 
pumps  hot  to  supply.  Always  save  your  air  and  keep  the 
pump  cool,  no  matter  what  length  of  train  you  handle. 

12.  Q.     Please  explain  what  excess  pressure  is. 

A.  Excess  pressure  is  the  difference  between  the  main 
reservoir  and  train  pipe  pressures  when  the  brake  valve  is 
in  running  position  so  that  the  excess  valve  or  the  feed 


50  EXCESS  PRESSURE 

valve  can  maintain  a  difference  between  the  two  pres- 
sures. In  full  release  position  these  valves  are  cut  out, 
but  the  air  can  pass  through  an  open  port  from  the  main 
reservoir  to  the  train  pipe  and  equalize,  so  in  release  po- 
sition there  is  no  excess.  If  you  carry  excess  you  aim  to 
prevent  this  equalization  and  thus  have  a  greater  amount 
of  air  in  main  reservoir  to  equalize  into  train  pipe  when 
necessary  to  release  brakes.  Of  course  it  takes  more  ex- 
cess to  promptly  release  all  the  brakes  on  a  long  train  than 
a  short  one.  When  releasing  brake,  it  supplies  the  train 
pipe  with  a  higher  pressure  than  brake  was  first  set  at; 
this  makes  the  movement  of  all  triples  to  release  position 
much  quicker  and  surer.  With  a  long  train  it  is  absolutely 
necessary  for  this  purpose.  On  a  long  train  excess  is 
needed  to  force  the  air  back  through  train  pipe  quickly 
and  release  brakes,  with  large  volume  to  hold  the  pressure 
up.  It  recharges  the  auxiliaries  quicker,  ready  for  the 
next  application  of  the  brake.  It  charges  empty  cars 
quicker  that  are  taken  on  the  train.  When  brakes  "  creep 
on,"  they  can  be  released  at  once  by  placing  the  brake 
valve  on  full  release  for  a  second  or  two,  just  long  enough 
to  raise  the  triple  to  exhaust  position  and  not  long  enough 
to  charge  the  reservoirs  to  a  higher  pressure,  then  return- 
ing it  to  running,  position. 

13.  Q.    Have  we  more  than  one  pattern  of  equalizing 
discharge  brake   valve? 

A.  Yes,  we  have  three  kinds  of  them  in  service,  called 
E-6,  or  F-6,  D-8  and  H-5,  from  the  number  of  the  plate 
on  which  each  is  illustrated  in  the  Westinghouse  catalogue. 
The  E-6  and  F-6  valves  are  exactly  alike  and  are  now 
known  as  the  "  1892  model "  or  F-6  valve.  Very  few  of 
the  D-8  valves  are  now  in  service.  The  H-5  brake  valve 
came  next  after  the  F-6  or  1892  model,  and  may  be  styled 
the  1906  model. 

14.  Q.     Describe  the  principle  on  which  it  operates 
and  what  difference  there  is  between  the  three  patterns. 

A.  This  brake  valve  has  a  rotary  valve  with  various 
ports  and  cavities  in  it  by  which  the  air  can  pass  to  and 


THE   BRAKE   VALVE  5 1 

from  the  various  pipes  and  connections  when  the  engineer 
moves  the  rotary.  It  also  has  a  piston  in  it  called  the 
equalizing  piston,  with  a  train  pipe  exhaust  valve  on  the 
bottom  side  of  it  which  is  designed  to  automatically  reduce 
the  train  pipe  pressure.  When  brake  valve  is  not  being 
operated  this  piston  has  an  equal  pressure  on  both  sides  of 
it,  so  it  remains  stationary,  holding  train  pipe  exhaust 
valve  closed.  When  it  is  used  to  set  the  brake,  the  reduc- 
tion of  air  pressure  is  not  made  by  the  engineer  direct  from 
the  train  pipe,  but  from  the  chamber  in  the  valve  over  the 
equalizing  piston  and  the  small  reservoir  connected  to  the 
chamber.  If  the  engineer  wishes  to  reduce  the  train  pipe 
pressure  any  specified  amount — say  seven  pounds — he 
moves  the  rotary  to  service  application  position.  As  the 
rotary  passes  lap  position,  the  ports  which  allow  the  air 
to  pass  from  one  part  of  the  brake  valve  to  another  are 
all  closed.  The  main  reservoir  air  is  held  on  top  of  the 
rotary  as  it  is  not  used  when  the  brake  is  set,  but  only 
when  releasing  or  charging  the  train  pipe  and  auxiliary 
reservoirs.  The  air  above  the  equalizing  piston  and  the 
brake  valve  reservoir  being  cut  off  from  all  other  air  may 
be  called  "  brake  valve  air ;"  it  is  what  operates  the  auto- 
matic part  of  the  brake  valve  to  equalize  the  discharge  of 
the  train  pipe  air,  which  is  below  the  piston.  When  the 
pressure  of  the  brake  valve  air  is  reduced  by  allowing 
some  of  it  to  escape  from  the  preliminary  exhaust  port, 
it  does  not  reduce  the  train  pipe  air  through  the  same 
opening;  so  the  equalizing  piston  having  less  pressure 
above  it,  raises  up,  opening  the  train  pipe  exhaust  valve 
on  the  bottom  of  this  piston  and  air  flows  out  of  the 
train  pipe.  As  soon  as  the  brake  valve  air  is  reduced  the 
amount  the  engineer  wishes  (and  the  amount  of  ^the  re- 
duction is  shown  with  the  black  hand  of  gage)  he  closes 
the  preliminary  exhaust  port  by  a  movement  of  the  rotary 
to  lap.  The  pressure  of  the  brake  valve  air  then  re- 
mains stationary ;  while  the  train  pipe  air  flows  out  through 
the  train  pipe  exhaust  till  it  is  reduced  a  little  lower  than 
the  brake  valve  air,  which  then  moves  the  piston  down 


THE   BRAKE  VALVE 


gradually  and  closes  the  train  pipe  exhaust.  It  takes  longer 
to  reduce  pressure  in  a  long  train  pipe  than  in  a  short 
one  through  the  small  train  pipe  exhaust  port  because  of 
the  greater  volume  of  air  in  the  long  pipe,  so  the  train 


(EQUALIZING  DISCHARGE  VALVE 

WITH  FEED  VALVE  ATTACHMENT. 

'  1892  MODEL. 

PLATE  D  5    PLATE  E*6. 
and    PLATE  F6. 


alike  in  construction 
and  operation t 

,  ».  Feecf  port. 


FEED  VAUVI 


pipe  exhaust  is  held  open  by  the  train  pipe  air  till  the 
pressure  is  reduced  the  whole  length,  then  closed  auto- 
matically by  the  pressure  of  the  brake  valve  air. 


THE   BRAKE  VALVE 


53 


Each  of  these  valves  uses  a  double  hand  gage  and  has 
a  small  reservoir  about  12  inches  long  connected  to  it  by  a 
small  pipe;  this  equalizing  reservoir  is  used  to  supply  the 
cavity  over  equalizing  piston  with  a  larger  volume  of  air, 
so  a  more  gradual  reduction  of  pressure  can  be  made 
through  the  preliminary  exhaust  port  from  this  cavity. 
The  later  size  of  this  reservoir  is  14^  inches  long;  it  con- 


-1&  Pw»  COVCRKOR  a  GAUCC 

-RCO  HANO- 

"MMN  FfcacHvo*  PR 


fern  VACVK 


tains  a  larger  volume  of  air  than  those  first  used  and  thus 
makes  the  reduction  of  brake  valve  air  more  gradual. 

In  illustration  on  page  52  the  main  reservoir  air  is  above 
the  rotary  43  in  A  and  feed  port  f.  The  train  pipe  air  is  in 
B  over  the  feed  valve  piston  74  and  in  C  under  the  equal- 
izing piston  47.  The  brake  valve  air  is  in  chamber  D  over 
piston  47  and  in  the  equalizing  reservoir  connected  to  brake 
valve  at  port  S.  The  brake  valve  air  is  connected  with 


54  THE   BRAKE   VALVE 

train  pipe  air  through  equalizing  port  g,  which  is  drilled 
through  the  seat  under  rotary  shown  by  dotted  lines  and 
more  plainly  on  another  page. 

Either  of  these  valves  when  placed  on  emergency  po- 
sition opens  a  large  port  which  lets  the  air  from  the  train 
pipe  direct  to  the  atmosphere,  making  a  sudden  reduction, 
which  causes  the  brake  to  go  on  suddenly  and  with  full 
force. 

The  small  bushing  that  restricts  the  flow  of  air  from 
chamber  D  out  of  preliminary  exhaust  of  D-8  valve  is 
located  in  port  h,  so  chamber  D  charges  through  port  e 
very  quickly  in  full  release.  The  seat  of  valve  near  e  is 
is  milled  out  so  air  can  pass  from  port  /  in  rotary  13  into  e 
until  rotary  is  very  close  to  running  position,  after  which 
air  goes  into  chamber  D  through  equalizing  port  g  only. 
This  prevents  any  lap  position  between  full  release  and 
running  position.  With  the  F-6  valve  or  1892  model  the 
ports  are  much  larger  so  there  is  no  chance  for  lap  in  this 
position.  With  F-6  valve  this  small  bushing  is  in  port  e, 
very  little  air  passes  through  it  into  D,  which  must  charge 
through  port  g. 

The  older  pattern  D-8  has  the  excess  valve  in  one 
side  where  it  can  be  taken  out  to  clean  or  regulate  when 
air  is  let  out  of  train  pipe.  When  the  brake  valve  is  on 
running  position  there  is  no  other  passage  for  the  air  to 
go  from  main  reservoir  to  train  pipe  except  by  this  valve 
and  it  is  held  on  its  seat  by  a  spring  which  is  stiff  enough 
to  maintain  about  20  pounds  difference  between  the  pres- 
sure in  train  pipe  and  main  reservoir  and  hold  the  excess 
in  main  reservoir.  The  pump  governor  is  piped  to  train 
pipe  and  set  at  70  pounds. 

The  F-6  has  a  reducing  or  feed  valve  attached  in  the 
place  of  the  excess  valve,  which  is  set  to  regulate  the  train 
line  pressure  at  not  over  seventy  pounds,  at  which  pressure 
it  closes  and  no  more  air  can  pass  to  train  pipe  from  main 
reservoir  till  the  train  pipe  pressure  falls  below  what  the 
-  feed  valve  is  set  at,  when  it  opens  again ;  with  this  valve 


DETAILS   OF    BRAKE   VALVE  55 

the  governor  is  piped  to  main  reservoir  and  set  at  ninety 
pounds. 

There  are  some  other  differences  in  the  construction  of 
these  valves  which  make  their  operation  a  little  different 
The  preliminary  exhaust  cavity  p  in  the  rotary  of  D-8 
valve  is  short,  so  that  as  soon  as  the  valve  is  moved  from 
service  application  to  emergency  position  the  prelimin- 
ary exhaust  port  is  lapped  or  covered,  and  the  pressure 
over  equalizing  piston  17  can  not  be  reduced  while  in  this 
position,  unless  air  leaks  out  past  piston  packing  ring  or 
through  joints. 

With  F-6  the  preliminary  exhaust  cavity  in  rotary  is  a 
long  groove,  so  preliminary  exhaust  port  is  open  from 
service  application  to  full  emergency.  This  can  let  all 
the  air  out  of  cavity  over  equalizing  piston — which  is 
named  chamber  D — and  equalizing  reservoir,  so  black  hand 
will  drop  back  to  nothing  as  soon  as  air  can  escape. 

With  D-8  the  running  position  feed  port  /  through 
rotary  comes  over  equalizing  port  g  when  at  a  certain 
place  on  emergency,  so  main  reservoir  pressure  can  get  in 
chamber  D  and  black  hand  will  show  the  same  pressure 
as  red  one.  In  this  position  there  is  no  air  in  train  pipe 
as  direct  application  port  is  open.  These  ports  do  not  con- 
nect with  each  other  in  the  F-6,  so  main  reservoir  air  can 
not  get  into  chamber  D  in  this  position.' 

With  D-8  set  on  the  ledge  between  running  position 
and  lap,  the  main  reservoir  pressure  is  shut  off  by  port 
j  closing  at  f,  so  no  air  can  -pass  through  to  train  pipe ; 
while  equalizing  port  g  remains  partly  open  and  train 
pipe  pressure  is  still  connected  directly  to  the  black  hand 
of  gage.  This  is  a  good  position  to  test  the  pressure 
in  the  auxiliaries,  for  when  the  train  pipe  and  auxiliaries 
have  equalized,  the  black  hand  will  become  stationary, 
unless  there  are  leaks  that  take  air  out  of  the  train  pipe. 

The  F-6  valve  will  not  show  this  way,  as  the  ports  f 
and  g  are  both  closed  at  the  same  time  by  the  movement 
of  rotary  43.  If  the  air  in  the  train  pipe  and  chamber  D 
can  equalize  past  piston  47  the  black  hand  will  show  train 


56  PIPING   THE   GOVERNOR 

pipe  pressure,  and  when  auxiliaries  have  equalized  with 
train  pipe,  it  will  show  both  pressures. 

T5-  Q-  Why  is  the  pump  governor  operated  by  the 
main  reservoir  air  pressure  with  the  F-6  or  1892  model 
brake  valve  and  by  the  train  pipe  air  pressure  with  the 
D-8  or  1889  model? 

A.  Because  the  feed  valve  attachment  or  train  pipe 
governor  on  the  1892  model  valve  regulates  the  flow  of  air 
into  the  train  pipe  while  the  valve  is  in  running  position  and 
maintains  its  pressure  very  closely  to  the  standard  amount, 
so  that  the  pump  governor  can  be  used  to  regulate  the 
main  reservoir  pressure,  therefore  the  pressure  it  regulates 
is  used  to  operate  the  governor. 

With  the  D-8  valve  the  excess  valve  21  does  not  regu- 
late the  train  pipe  pressure,  it  can  only  be  used  to  main- 
tain a  difference  of  pressure  between  the  main  reservoir 
and  train  pipe.  With  an  engine  and  tender  only,  the 
spring  and  valve  may  be  adjusted,  so  this  difference  may 
be  twenty  pounds  exactly;  while  if  a  long  train  is 
attached  it  will  be  considerably  more,  the  air  will  not  pass 
this  excess  valve  freely  enough  to  hold  up  the  pressure  in  a 
long  train  as  easily  as  in  a  short  one.  Train  pipe  leaks 
affect  this  and  the  excess  spring  19  gets  stronger  as  it 
is  compressed,  so  that  it  takes  more  difference  in  pressures 
to  hold  it  open  and  supply  leaks  in  a  long  train  than  in  a 
short  one,  as  there  are  usually  more  of  them.  If  the 
governor  was  operated  by  main  reservoir  pressure  from 
the  D-8  valve  and  set  at  ninety  pounds,  the  train  pipe 
pressure  for  one  train  could  be  adjusted  to  seventy  pounds 
by  getting  the  excess  spring  just  right.  If  this  engine 
were  attached  to  another  train  the  train  pipe  pressure 
would  likely  be  more  or  less  than  seventy.  Now,  seventy 
pounds  is  what  we  want  for  safe  work  with  any  train  or 
engine,  as  the  excess  valve  can  not  regulate  the  train  pipe 
pressure  properly  and  the  pump  governor  can,  the  gov- 
ernor is  operated  by  train  pipe  pressure  and  set  at  seventy 
pounds  for  all  trains. 


F-6   FEED    VALVE 


57 


By  the  use  of  a  Duplex  governor,  which  consists  of  two 
complete  diaphram  bodies  coupled  with  a  tee  connection 
to  one  steam  valve  body,  having  one  air  diaphram  con- 
nected to  the  train  pipe  and  set  at  seventy  pounds,  the 
other  connected  to  the  main  reservoir  and  set  for  the 
desired  main  reservoir  pressure;  both  train  pipe  and  main 


FEED 


reservoir  pressure  can  be  regulated  while  the  brake  valve 
is  on  running  position.  On  full  release  position  the  side 
of  the  governor  set  at  the  lowest  pressure  will  stop  the 
pump  at  that  pressure.  On  service  application  the  train 
pipe  side  of  governor  will  be  cut  out  and  the  one  coupled 
to  the  main  reservoir  will  stop  the  pump. 

16.     Q.     Describe  the  feed  valve  of  train  pipe  pressure 


58  OPERATION    OF    FEED    VALVE 

regulator.  How  many  kinds  are  in  use  and  what  are  the 
differences  in  their  operation? 

A.  There  are  three  forms  of  the  feed  valve  in  general 
use.  The  older  one,  called  F-6,  has  a  poppet  valve,  63, 
which  is  opened  and  closed  by  the  movement  of  a  piston, 
74,  which  piston  is  moved  in  one  direction,  down,  by  the 
pressure  of  the  train  pipe  air,  and  up  by  a  regulating 
spring,  68. 

When  the  feed  valve  63  is  open,  as  shown  in  the  illus- 
tration, the  main  reservoir  air  which  comes  from  the  brake 
valve  when  in  running  position,  comes  through  /,  passes 
by  valve  63  into  cavity  B,  as  shown  by  the  arrow,  and  out 
through  port  i  into  the  train  pipe.  Piston  74  is  held  up 
against  the  train  pipe  pressure  in  B  by  the  regulating 
spring  68,  which  is  adjusted  to  hold  the  piston  up  so  the 
supply  valve  will  not  close  till  the  pressure  reaches  the 
standard  amount,  usually  seventy  pounds ;  at  which  pres- 
sure the  piston  is  moved  down  for  enough  to  allow  valve 
63  to  close  on  its  seat  and  shut  off  the  supply  of  main 
reservoir  air  passing  into  the  train  pipe. 

If  from  any  cause  the  train  pipe  pressure  is  reduced 
below  the  standard  amount,  the  regulating  spring  pushes 
the  piston  and  valve  63  up,  so  that  air  passes  from  the 
main  reservoir  to  the  train  pipe.  This  action  of  the  feed 
valve  maintains  the  pressure  in  the  train  pipe  at  the 
standard  amount  steadily,  provided  there  is  enough  in  the 
main  reservoir. 

The  train  pipe  pressure  begins  to  move  the  piston  down 
against  the  stiffness  of  the  regulating  spring  at  about  forty- 
five  pounds,  so  that  valve  63  begins  to  close  a  little  at  that 
pressure.  As  the  pressure  increases  it  compresses  the 
spring  more,  until  at  seventy  pounds  piston  74  is  down  so 
the  valve  63  has  entirely  closed.  On  account  of  this  action 
of  the  F-6  feed  valve  the  passage  of  air  from  the  main 
reservoir  to  the  train  pipe  was  free  up  to  forty-five  or  fifty 
pounds,  and  was  then  gradually  restricted  as  the  pressure 
raised,  so  that  between  sixty-five  and  seventy  pounds  the 


FEED  VALVE  DEFECTS  59 

opening  was  so  small  that  with  a  long  train  or  much  leak- 
age it  took  a  long  time  to  feed  up  between  those  pressures. 

To  stop  the  piston  in  case  the  brake  valve  is  in  full 
release  position,  the  lower  part  of  the  piston  comes  against 
the  top  part  of  the  spring  case  69,  in  the  illustration  the 
piston  is  shown  in  this  position,  in  service  it  moves  down 
only  far  enough  to  allow  valve  63  to  close.  The  small 
spring  64  closes  the  valve  wjhen  the  piston  moves  down. 

The  two  gaskets  72  are  intended  to  stop  any  train  pipe 
air  leaking  by  the  piston.  There  is  a  recess  in  the  bush- 
ing ring  75  deep  enough  to  hold  the  smaller  gasket  when 
the  piston  is  down.  If  this  gasket  is  too  thick  for  this 
recess  it  will  hold  up  the  piston  and  feed  valve  so  that  the 
train  pipe  pressure  will  get  too  high.  If  the  spring  case 
69  is  screwed  up  too  far  into  the  valve  body  62,  the  edge  of 
the  larger  gasket  will  be  smashed  out  thin,  the  two  gaskets 
will  then  fill  the  recess  in  75  and  hold  the  piston  up  and 
valve  63  open,  which  will  allow  train  pipe  pressure  to  feed 
up  too  high. 

If  the  stem  of  valve  63  that  runs  up  into  the  cap  nut 
65  gets  bent,  the  valve  will  not  seat  squarely,  and  air  will 
leak  past  it  steadily. 

A  leak  through  the  gasket  56  from  port  f  to  port  i  will 
allow  air  to  pass  from  the  main  reservoir  to  train  pipe 
without  passing  valve  63. 

Do  not  confound  this  leak  with  a  leak  through  gasket 
61  in  the  brake  valve,  which  allows  the  air  from  main 
reservoir  to  flow  into  chamber  D  in  any  position  except 
full  release.  A  leak  through  the  feed  valve  affects  the 
pressures  in  running  position  only,  as  that  is  the  only 
position  in  which  air  can  pass  the  rotary  to  the  feed  valve. 

The  feed  valve  attachment  must  be  kept  clean  if  it  is 
expected  to  work  correctly.  If  the  valve  63  gets  gummy 
so  that  it  is  not  air  tight  on  its  seat,  the  main  reservoir 
will  tend  to  equalize  with  the  train  pipe  at  more  than  the 
standard  amount. 

The  Slide  Valve  Feed  Valve,  G-6,  which  is  a  later  type 


6o 


SLIDE  VALVE — FEED  VALVE 


than  the  F-6,  is  shown  in  two  positions,  has  a  slide  valve 
55,  to  open  and  close  the  air  supply  port  b,  and  allow  air 
to  pass  from  the  main  reservoir  to  the  train  pipe  when  the 
rotary  is  in  running  position.  This  supply  valve  is  operated 
by  a  piston,  54,  which  is  moved  in  one  direction  by  the 
main  reservoir  air  pressure,  in  the  other  by  a  spring,  58. 

To  aid  the  reader  we  have  prepared  two  sketches  of 
this  feed  valve  in  which  the  ports  and  passages  are  shown 


Fig.  i. 


Fig.  2. 


in  such  relations  to  each  other  that  the  flow  of  air  through 
the  complete  valve  may  be  more  easily  understood.  Figs, 
i  and  2  show  the  valve  as  it  really  is,  in  the  normal  posi- 
tion, with  no  main  reservoir  air  in  it,  on  the  next  page 
are  shown  the  diagrammatic  sketches  spoken  of. 

With  the  G-6  feed  valve  the  pressure  of  the  main  reser- 
voir air  against  the  piston,  54,  must  be  sufficient  to  push 


G-6  FEED  VALVE 


6l 


it  over  against  the  strength  of  the  spring  58,  before  the 
slide  valve  will  be  moved  to  uncover  port  b.  With  this 
valve  at  work  feeding  up  the  train  pipe  the  main  reservoir 
will  show  slight  excess  pressure  at  all  times.  This  you  do 
not  see  with  the  F-6  valve,  as  its  feed  valve  is  not  held 
open  by  the  main  reservoir  pressure. 

Main   reservoir   air   enters   at   /,   passes   into  the   slide 
valve  chamber  F  on  top  of,  around  the  ends  and  sides  of 


SUIDE 


SLIDE-VALVE  FEED  VA.LVE. 
CLOSED   POSITION 

55  58 


valve  55  and  against  piston  54.  Chamber  E,  on  the  other 
side  of  the  piston,  is  connected  through  passage  c  with  the 
chamber  around  regulating  valve  59,  and  if  this  valve  is 
open,  air  from  E  will  pass  through  a  into  the  train  pipe 
through  i,  so  that  air  in  E  can  equalize  with  that  in  the. 
train  pipe. 

A  diaphram,  57,  which  consists  of  two  thin  brass  sheets 
similar  to  the  governor  diaphram,  keeps  the  train  pipe  air 


62  G-6  FEED  VALVE 

from  escaping  to  the  atmosphere  through  the  spring  case, 
this  diaphram  rests  on  a  piston,  64,  which  is  held  up  by 
the  regulating  spring  67.  The  stem  of  the  regulating 
valve  59,  rests  against  this  diaphram,  when  57  moves  over, 
the  regulating  valve  moves  with  it.  With  reservoir  pres- 
sure in  F  and  train  pipe  pressure  in  E,  the  piston  and  slide 
valve  moves  from  the  position  shown  in  Fig.  2  to  that 
shown  in  Fig.  3,  so  that  the  port  is  open  at  b,  allowing  air 
to  pass  from  f  to  i.  Piston  54  is  not  a  tight  fit  in  its 
bushing,  while  the  main  reservoir  pressure  is  holding  it 
over  against  the  spring  58,  air  is  leaking  by  the  piston 
steadily  from  F  into  E  and  thence  through  passage  c,  past 
the  regulating  valve  and  passage  a  into  the  train  pipe ;  in 
addition  to  what  goes  in  at  port  b. 

When  the  train  pipe  pressure  reaches  the  standard 
amount  it  has  moved  the  diaphram  and  its  piston  over 
against  the  resistance  of  spring  67  and  allowed  valve  59  to 
seat  as  shown  in  Fig.  4.  This  stops  the  passage  of  air 
from  E  to  the  train  pipe,  piston  54  not  being  an  air 
tight  fit,  air  from  F  soon  equalizes  with  E.  Spring  58, 
which  was  compressed  when  the  piston  moved  towards  E, 
now  reacts,  pushes  54  and  55  back  into  the  position  shown 
in  Fig.  4,  this  stops  the  flow  of  air  through  b  into  the  train 
pipe,  as  the  regulating  valve  has  stopped  the  flow  of  air 
from  E,  no  more  air  passes  in  at  either  place,  and  the 
train  pipe  pressure  will  not  rise  any  higher..  When  the 
train  pipe  pressure  falls  below  the  standard  amount,  the 
regulating  spring  will  move  the  piston  64  and  diaphram 
enough  to  unseat  valve  59,  air  in  E  can  then  equalize  with 
the  train  pipe,  reservoir  pressure  in  F  at  once  moves  the 
piston  and  slide  valve  as  shown  in  Fig.  3  and  air  feeds 
into  train  pipe  again. 

If  the  regulating  valve  leaks,  if  either  of  the  cap  nuts 
53  or  61  leak,  or  if  the  spring  58  is  too  weak,  or  gone,  the 
piston  will  hold  slide  valve  open  so  that  train  pipe  pres- 
sure may  get  too  high.  If  the  opening  by  the  seat  of  the 
regulating  valve  is  stopped  up,  or  the  regulating  spring  is 


B-4   FEED   VALVE 


63 


too  weak,  the  slide  valve  will  be  closed.  To  clean  valve 
59  leave  rotary  in  service  position  and  take  off  cap  nut  61. 
To  clean  piston  54  remove  cap  nut  53.  Piston  54  has  no 
packing  rings,  it  should  be  clean  and  free  from  gum. 

The  B-4  feed  valve  is  much  the  same  as  the  G-6,  but  has 
a  small  port  f  drilled  through  the  piston  8  and  a  packing 
ring  9,  that  regulates  the  supply  of  main  reservoir  air 
passing  into  the  chamber  G  behind  the  piston.  In  all  re- 
spects the  operation  of  the  piston  with  its  supply  valve,  and 
the  regulating  valve  is  the  same  as  the  G-6  feed  valve. 


:UVERY 


23 


DIAGRAM  OF  FEED  VALVE,  CLOSED 


DIAGRAM  OF  FEED  VALVE,  OPEM 


But  there  is  a  quick  thread  screw  on  the  regulating  nut 
23  that  allows  a  change  to  be  made  in  the  tension  of  the 
regulating  spring  18  so  that  the  pressure  of  the  train  pipe 
air  can  be  changed  from  70  to  no  pounds,  or  vice  versa, 
by  a  partial  revolution  of  the  small  hand  wheel  that  is 
part  of  the  regulating  nut  23.  Secured  to  the  spring  case 
19  are  two  split  rings,  20  and  21,  a  small  screw  22  binds 
the  ends  of  the  split  ring  when  once  adjusted  so  it  cannot 
slip  around  on  the  spring  case  19.  The  feed  valve  is  first 
adjusted  to  close  at  the  lower  pressure,  say  70  pounds,  and 


64  BLACK    HAND    PRESSURE  . 

the  split  ring  21  brought  against  the  pin  fixed  in  the  hand 
wheel  23.  The  wheel  and  adjusting  nut  23  are  now  turned 
to  increase  the  tension  on  the  spring  18  till  the  valve  will 
close  at  the  higher  pressure,  say  no  pounds,  and  the  split 
ring  22  is  moved  against  the  other  side  of  the  pin  in  23. 
By  turning  23  so  the  pin  rests  against  one  or  the  other  of 
the  stops  on  the  rings  21  or  22,  the  tension  of  the  spring 
is  adjusted  for  the  proper  pressures.  This  type  of  feed 
valve  is  usually  attached  to  a  pipe  bracket,  as  shown  in 
the  cut,  but  it  can  be  attached  to  the  1892  model  valve  the 
same  as  the  G-6  feed  valve.  When  so  used  it  will  do 
away  with  the  pipe  bracket,  the  reversing  cock  and  one  of 
the  two  G-6  feed  valves  used  with  the  high  speed  brake. 

17.  Q.     What   pressure    does    the   black   hand    of   the 
double   gage   show,   and   why? 

A.  It  shows  the  pressure  in  chamber  D  above  the 
equalizing  piston  in  the  brake  valve,  and  in  the  brake 
valve  reservoir,  it  is  connected  to  the  pipe  from  chamber 
D  to  the  small  reservoir  and  not  to  the  train  pipe.  It  is 
connected  in  this  manner  because  when  applying  the 
brake  the  engineer  must  know  exactly  how  much  he 
reduces  the  brake  valve  pressure  over  the  equalizing  pis- 
ton, therefore  the  black  hand  must  show  the  exact  pres- 
sure there  while  making  a  service  reduction.  If  the  brake 
is  set  with  a  direct  or  emergency  application  the  gage  does 
not  at  once  show  the  exact  train  pipe  reduction. 

18.  Q.     In  what  position  of  brake  valve   does  it  also 
show  the  exact  train  pipe  pressure? 

A.  Full  release,  running  position,  or  anywhere  between 
full  release  and  lap.  In  these  positions  the  equalizing 
port  g  which  is  the  communication  between  the  train  pipe 
and  the  chamber  D,  is  open.  In  any  other  position  this 
port  is  shut  to  the  train  pipe  pressure  so  it  is  not  connected 
to  the  black  hand  direct. 

19.  Q.     Then  the  black  hand  does  not  show  the  exact 
train  pipe  pressure  when  on  lap  or  past  lap  towards  the 
emergency   position  ? 


EXCESS    PRESSURE  65 

A.  No,  not  immediately,  and  you  can  easily  prove  this 
by  placing  the  valve  on  lap  and  opening  the  angle  cock  at 
rear  end  of  tender ;  the  train  pipe  pressure  will  drop  to 
nothing  at  once,  which  the  black  hand  will  not  do.  Usually 
the  equalizing  piston  packing  ring  leaks  a  little,  and  the 
black  hand  will  drop  back  slowly  as  the  air  leaks  out  into 
the  empty  train  pipe;  if  there  are  no  leaks  in  the  brake 
valve,  or  connections  to  gage  or  brake  valve  reservoir,  it 
will  not  drop  any.  Unless  the  packing  ring  leaks  consid- 
erable it  does  little  harm.  A  very  small  leak  is  an  advan- 
tage as  it  will  show  on  the  black  hand  the  train  pipe  pres- 
sure as  soon  as  the  pressures  can  equalize  past  the  piston, 
it  can  warn  the  engineer  if  valve  is  left  on  lap  and  train 
pipe  pressure  falls  slowly  without  setting  the  brake. 

20.  Q.     What    difference    between    the    D-8    and    F-6 
valves  in  regard  to  carrying  excess  pressure? 

A.  With  D-8  valve  or  any  brake  valve  using  an  excess 
valve  to  maintain  the  excess  pressure,  when  placed  in 
running  position,  you  get  the  excess  pressure  before  the 
train  line  begins  to  raise  any,  no  matter  at  what  pressure 
you  start,  as  the  main  reservoir  pressure  must  raise  enough 
first  to  get  by  the  excess  valve  before  going  into  train  pipe. 
With  the  1892  model,  both  pressures  raise  together  till 
train  pipe  stands  at  seventy  pounds,  then  the  feed  valve 
shuts  and  excess  begins  to  pick  up  in  main  reservoir.  So 
you  have  excess  first,  with  D-8  valve,  and  hold  it  while 
valve  is  in  running  position ;  with  F-6,  you  get  train  pipe 
pressure  first  up  to  seventy  pounds,  then  excess  after- 
wards. 

21.  Q.     When  the  D-8  valve  has  been  left  on  release 
position  till  train  line  and  main  reservoir  have  equalized  at 
seventy  pounds,   and   is   then   placed   on   running  position, 
are  the  brakes  apt  to  creep  on  at  once?    Why  is  this? 

A.  When  the  D-8  valve  is  placed  on  running  position, 
it  shuts  off  the  air  from  train  line  till  the  excess  pressure 
is  picked  up  in  the  main  reservoir,  before  this  excess  is 
picked  up  if  the  train  line  leaks,  the  brake  will  set.  In 


66  EXCESS    PRESSURE 

such  a  case,  run  your  pump  a  little  faster  for  a  few  min- 
utes— not  over  five — so  as  to  get  the  excess  quicker.  If 
train  is  under  motion  and  you  feel  a  brake  dragging,  put 
the  brake  valve  in  full  release  for  a  second  only,  then 
place  it  in  running  position;  this  may  have  to  be  done  a 
second  or  third  time  until  air  begins  to  go  through  excess 
pressure  valve,  when  it  will  hold  brakes  off.  A  short  rule 
for  this  is:  Keep  your  excss  all  the  time  by  not  using 
the  full  release  position,  except  at  the  time  of  releasing  the 
brakes,  then  running  position  will  hold  them  off. 

22.  Q.  Please  state  the  different  positions  of  the  brake 
valve,  the  course  the  air  takes  passing  through  it,  and 
what  ports  are  covered  in  each  position. 

NOTE — To  aid  the  student  we  have  prepared  some 
sketches  of  the  D-8  brake  valve  in  which  the  rotary  13  is 
shown  as  if  it  were  a  long  valve  sliding  in  a  straight  line 
back  and  forth  over  a  valve  seat  instead  of  turning  on  a 
center  as  the  actual  rotary  valve  really  does.  In  these 
sketches  the  rotary  is  shown  as  if  cut  between  the  prelim- 
inary exhaust  cavity  p  and  the  emergency  exhaust  cavity 
and  straightened  out  as  a  hoop  is  straightened  out  when 
cut  across.  The  ports  are  shown  in  somewhat  changed 
positions  so  they  will  be  in  proper  communication  with  the 
ports  and  cavities  in  the  sliding  valve  13.  Ports  a  and  g 
are  shown  in  the  sketch  as  if  they  communicated  with  each 
other,  in  the  actual  rotary  valve  a  is  nearer  the  center 
than  g,  so  in  service  they  do  not  register  with  each  other. 
In  actual  service  port  /  registers  with  f  in  running  position 
as  shown,  and  with  port  g  in  emergency  position;  but  for 
the  purposes  of  explanation  the  sketch  gives  a  very  good 
idea  of  the  course  of  the  air  in  the  various  positions  of  the 
D-8  valve. 

A.  When  on  full  release  position,  main  reservoir  air 
which  comes  in  the  brake  valve  on  top  of  the  rotary  can 
pass  through  opening  a  in  the  rotary  into  a  cavity  in 
the  rotary  valve  seat  b  and  from  there  around  the  bridge 
in  rotary  and  into  the  train  pipe  direct;  in  this  position 


FULL    RELEASE 


68 


DIAGRAMMATIC   BRAKE   VALVE 


the  main  reservoir  and  train  pipe  pressures  can  equalize. 
The  air  from  main  reservoir  also  passes  through  the  feed 
port  /  in  rotary  valve  into  the  supply  port  e  for  the  pre- 
liminary exhaust  and  down  into  chamber  D.  Air  can  also 
pass  into  chamber  D  from  the  train  pipe  cavity  c  in  rotary 
valve  through  eqaulizing  port  g.  In  this  position  the 
warning  port  is  open  so  main  reservoir  air  blows  through 
rotary  into  main  exhaust  port.  The  preliminary  exhaust 
and  emergency  exhaust  ports  are  closed  as  well  as  the  feed 
port  f  leading  to  the  excess  valve  or  feed  valve. 

When  on  the  next  position,  called  running  position 
because  it  is  the  proper  position  when  train  is  running 
with  brakes  released,  the  direct  supply  port  is  covered  so 
that  main  reservoir  air  can  not  get  into  train  pipe  direct, 
the  supply  port  c  is  also  covered  so  no  main  reservoir  air 
can  pass  through  into  chamber  D.  The  feed  port  f  is 


opened  and  main  reservoir  air  must  then  pass  through  this 
port  and  go  past  the  excess  valve  or  feed  valve  to  get  into 
the  train  pipe.  Train  pipe  air  can  pass  through  the  cavity 
c  under  rotary  and  go  through  port  g  into  chamber  D  and 
equalize  the  pressure  on  both  sides  of  the  equalizing  pis- 
ton. The  small  warning  port  is  covered.  On  lap  position 
all  ports  are  closed  so  no  air  can  pass  under  or  through 
the  rotary.  On  service  application  position  the  prelimin- 


70  LEAKS 

ary  exhaust  port  h  is  opened  so  air  flows  out  of  chamber 
D;  this  is  done  by  a  movement  of  the  rotary,  the  equal- 
izing piston  opens  the  train  pipe  exhaust  port  automatic- 
ally. All  other  ports  are  closed, 

On  emergency  position  the  direct  application  port  is 
opened,  allowing  the  air  in  the  train  pipe  to  pass  directly 
to  the  atmosphere  through  the  cavity  under  the  rotary. 
As  this  is  the  largest  port  in  the  brake  valve,  if  it  is  opened 
wide  the  air  in  the  train  pipe  will  escape  suddenly. 

With  D-5,  E-6  and  F-6  valve,  the  preliminary  exhaust 
port  is  left  open.  All  other  ports  are  closed.  With  D-8 
valve  when  on  a  certain  part  of  this  position  the  port  /  in 
rotary  comes  over  the  equalizing  port  g  so  main  reservoir 
air  passes  into  chamber  D.  This  port  does  not  open  in  the 
other  brake  valves.  The  port  from  brake  valve  to  brake 
valve  reservoir  is  open  at  al'l  times. 

23.  Q.  Do  leaks  in  the  brake  valve  interfere  with  its 
work? 

A.  Yes ;  if  there  is  a  leak  under  the  rotary  valve  from 
the  main  reservoir  to  train  pipe,  the  train  pipe  pressure 
will  raise  so  that  the  brake  will  release  when  valve  is  on 
lap.  A  leak  from  train  pipe  under  rotary  valve,  or  through 
train  pipe  discharge  valve  to  atmosphere,  or  a  leak  between 
equalizing  reservoir  and  brake  valve  when  valve  is  on  lap, 
will  set  the  brake  tighter  than  you  want  it.  If  it  leaks 
through  gasket  from  main  reservoir  to  cavity  over  equal- 
izing piston  47  in  F-6  valve,  or  past  gasket  18  in  the  H-5 
valve,  brake  cannot  be  set  in  service  application,  as  air  will 
flow  into  chamber  D  from  main  reservoir  as  fast  as  it 
flows  out  of  preliminary  exhaust.  Using  the  brake  valve 
on  emergency  habitually  will  tend  to  cut  the  rotary  and 
seat  quicker,  as  it  brings  sand  and  scales  of  iron  rust  up 
from  the  train  pipe  on  the  seat,  which  the  service  applica- 
tion will  not  do.  If  the  brake  -valve  is  fastened  close  to  the 
boiler  head  so  it  gets  very  hot,  the  leather  gaskets  get 
burned  and  crack  so  they  leak  badly.  A  bad  leak  past  the, 
equalizing  piston  will  cause  engine  brakes  to  release  when 
set  with  a  light  direct  application.  This  is  because  air 


DISABLED    BRAKE    VALVE  71 

leaks  from  equalizing  reservoir  past  piston  and  raises  train 
pipe  pressure  in  the  short  train  pipe  on  engine  and  tender. 
This  leak  will  also  prevent  the  equalizing  piston  raising 
when  making  a  service  reduction  if  the  air  can  come  past 
the  piston  into  chamber  D  as  fast  as  it  is  discharged 
through  preliminary  exhaust  port.  It  also  makes  the  train 
pipe  reduction  less  than  the  gage  at  first  shows,  on  a  long 
train. 

24.  Q.    What  is  the  effect  if  equalizing  reservoir  pipe 
is  broken  so  a  blind  joint  has  to  be  made? 

A.  The  brake  cannot  be  set  with  a  gradual  application 
in  service  position;  there  is  so  little  air  above  the  equal- 
izing piston,  it  escapes  out  of  preliminary  exhaust  so 
quickly  that  the  pressure  above  piston  is  reduced  more 
than  20  pounds,  equalizing  piston  stays  up  and  the  brake 
works  with  full  application;  some  times  emergency  with  a 
very  short  train. 

25.  Q.    What  should  you  do  in  such  a  case? 

A.  If  joints  cannot  be  made  so  as  to  use  equalizing 
reservoir  again,  a  blind  joint  should  be  made  at  its  con- 
nection with  brake  valve;  the  elbow  in  train  pipe  exhaust 
should  be  plugged  and  valve  used  with  direct  application 
port,  taking  care  to  make  a  gradual  reduction  so  brake 
will  not  go  on  with  emergency,  and  closing  valve  slowly 
so  the  brakes  on  head  end  will  not  be  kicked  off.  The 
elbow  has  a  thread  cut  in  it  for  plugging;  if  it  is  not 
threaded  take  it  out  and  plug  the  hole  with  the  plug  in 
the  equalizing  reservoir.  A  y%  plug  is  used  with  the 
H-5  valve. 

26.  Q.     With  the  equalizing  discharge  valve,  why  does 
the  air  blow  out  of  the  train  pipe  exhaust  when  brake  is 
released,  if  working  brake  on  engine  and  tender  only? 

A.  Because  the  train  pipe  is  charged  up  through  a 
large  hole  in  rotary  valve ;  the  cavity  over  equalizing  piston 
and  brake  valve  reservoir  is  charged  from  the  main  reser- 
oir  through  the  small  supply  port  e  for  preliminary  ex- 
haust, and  by  equalizing  port  g.  If  the  train  pipe  is  short, 
it  will  charge  up  to  a  full  pressure  quicker  than  the  space 


72  TRAIN    PIPE    EXHAUST 

above  piston;  train  pipe  pressure  will  then  raise  piston 
and  discharge  valve,  allowing  air  to  blow  out  of  train  pipe 
exhaust  elbow  for  a  second  or  two.  This  flash  of  air  is 
not  as  heavy  with  the  D-8  valve  as  with  the  later  patterns. 
The  D-8  valve  has  a  larger  opening  through  supply  port  e. 
There  is  no  flash  of  air  from  the  H~5  brake  valve  when 
coupled  to  any  cars. 

27.  Q.     Can  this  action  of  the  valve  be  of  advantage 
to  you? 

A.  Yes;  if  you  hear  this  escape  of  air  from  train  pipe 
exhaust  when  releasing  brake  on  a  train,  it  is  a  sign  of  a 
short  train  pipe;  and  is  a  notice  to  the  engineer  that  an 
angle  cock  at  the  head  end  of  train  is  closed,  or  something 
has  got  into  the  train  pipe  and  stopped  it  up.  You  should 
see  at  once  if  an  angle  cock  is  not  shut  by-  some  mistake 
or  malicious  intent.  Check  chains  swinging  against  the 
handle  will  close  it. 

28.  Q.     Does  the  amount  of  air  which  blows  out  of 
train  pipe  exhaust  when  setting  the  brake  with  a  service 
application  give  you  any  idea  of  the  number  of  cars   in 
your  train  working  air? 

A.  Yes,  with  engine  and  tender  only,  the  train  pipe 
exhaust  does  not  blow  much,  if  any,  longer  than  pre- 
liminary exhaust.  With  a  long  train  it  takes  some  seconds 
for  the  train  pipe  pressure  to  be  reduced  and  equalize  its 
whole  length.  You  can,  after  some  practice,  tell  whether 
you  have  a  long  or  short  train  working  air  by  listening  to 
the  amount  of  air  escaping  from  train  pipe  exhaust.  This 
test  shows  the  length  of  train  pipe  cut  in  and  filled  with 
air,  not  the  number  of  brakes  that  set.  It  takes  consider- 
able practice  to  tell  how  many  cars  are  coupled  on.  By 
this  test  it  gives  the  number  of  car  lengths  of  train  pipe 
in  use;  if  the  triple  is  cut  out  on  any  car  it  gives  you  no 
notice.  When  some  of  the  cars  are  cut  out  by  closing 
angle  cocks,  a  less  amount  of  air  will  come  out  than  with 
all  of  them.  It  is  important  to  know  this,  as  some  of  the 
angle  cocks  may  be  closed,  thus  cutting  off  all  the  cars 
behind  the  closed  one.  In  making  a  test  for  the  length  of 


TESTING  LENGTH  OF  TRAIN  PIPE  73 

train  pipe  connected  to  the  brake  valve,  reduce  your  brake 
valve  pressure  exactly  five  pounds  by  the  gage  and  then 
note .  the  amount  or  air  coming  out  of  the  train  pipe  ex- 
haust. Always  use  the  same  amount  of  reduction  as  there 
is  no  sure  way  to  compare  the  length  of  train  pipe  exhaust 
for  different  trains  unless  the  same  brake  valve  reduction 
is  used  as  a  measure  each  time.  A  partly  opened  angle 
cock  can  be  detected  by  this  test,  for  the  air  will  flow  with 
a  strong,  steady  sound  from  the  train  pipe  ahead  of  the 
partly  opened  cock,  while  the  air  from  the  pipe  behind  it 
will  string  out  longer  and  weaker  than  it  should.  Look 
out  for  this,  as  the  brakes  can  all  be  set,  but  as  the  air 
equalizes  very  slowly  into  the  rear  cars  some  of  the  triples 
in  rear  cars  are  liable  to  stick.  With  a  full  train  of  quick- 
service  triples  considerable  train  pipe  air  goes  through 
these  triples  to  the  brake  cylinder;  so  a  less  amount  of  air 
will  come  out  of  the  brake  valve  from  the  train  pipe  than 
with  the  older  form  of  triples. 

29.  Q.    What  is  the  stop  cock  under  brake  valve  for? 
Will  it  assist  you  in  locating  leaks  ?     How  ? 

A.  To  cut  out  the  train  pipe  from  brake  valve  when 
"  double  heading,"  so  only  one  engineer  can  control  all 
the  brakes.  For  this  purpose  it  is  absolutely  necessary. 
Yes,  it  will  assist  in  locating  leaks.  When  shut,  after 
charging  train  pipe  and  auxiliaries,  if  there  is  a  leak  in 
train  pipe,  brake  will  set  at  once;  if  the  rotary  leaks  either 
into  or  out  of  the  train  pipe,  it  will  show  it  very  soon,  as 
there  is  so  short  a  train  pipe  to  leak  into  or  out  of.  A 
little  observation  will  teach  you  many  ways  of  using  this 
cut-out  cock  in  testing  for  leaks.  With  the  H-5  valve 
and  the  distributing  valve  this  stop  cock  controls  the  ex- 
haust from  the  distributing  valve. 

30.  Q.    If  you  had  an  1892  valve  and  the  brake  would 
not  go  on  in  service  application,  nor  the  black  hand  fall, 
nor  the  train  pipe  exhaust  open,  while  air  came  readily 
from  preliminary  exhaust,  what  would  be  the  matter? 

A.  I  would  look  for  a  leak  at  the  joint  on  lower  gasket 
where  a  leak  would  allow  air  to  get  from  main  reservoir 


74  LEAKS 

direct  to  cavity  over  equalizing  piston  No.  47.  This  would 
give  main  reservoir  pressure  to  chamber  D  and  show  it  on 
the  black  hand.  A  brake  valve  with  this  leak  would  show 
no  excess  pressure.  No  air  could  come  out  of  train  pipe 
exhaust,  as  the  pressure  could  not  be  reduced  over  the 
piston  so  valve  could  be  raised.  To  set  the  brake  use  di- 
rect application  port,  opening  and  closing  it  slowly. 

31.  Q.     If  you  had  a  continual  blow  at  the  train  pipe 
exhaust  port  of  the  brake  valve  and  could  hold  no  air, 
where  would  the  difficulty  be  apt  to  be  found? 

A.  Stuck  or  leaky  equalizing  piston,  dirt  on  its  valve 
seat,  brake  valve  reservoir  bleed  cock  open,  or  bad  leak  in 
pipe  to  brake  valve  reservoir  or  gage.  Would  put  valve 
on  lap,  then  on  emergency  for  a  moment  and  see  if  that 
would  stop  it,  or  close  the  stop  cock  under  the  valve  and 
flash  the  valve  to  clean  off  the  seat. 

32.  Q.     How  should  the  brake  valve  handle  be  placed 
when    running    or    standing    with    brake    released,    unless 
auxiliaries  are  being  charged  ?    Why  ? 

A.  Always  in  running  position.  Because  this  is  the 
only  position  in  which  you  can  carry  excess  pressure, 
which  is  needed  to  release  brakes  promptly.  With  1892 
valve  on  full  release  the  train  pipe  pressure  will  run  up  as 
high  as  pump  governor  will  allow;  this  high  pressure  is 
apt  to  slide  the  wheels.  A  small  blow  hole  is  put  in  the 
rotary  valve  to  warn  engineer  that  valve  has  been  left 
in  full  release.  All  valves  should  have  this  warning  port; 
if  it  gets  stopped  up,  it  is  a  sign  that  there  is  dirt  on 
top  of  rotary  valve,  which  should  be  taken  out  and  cleaned 
at  once.  When  on  running  position  the  opening  through 
brake  valve  from  main  reservoir  to  train  pipe  is  a  smaller 
one  than  on  full  release.  If  the  train  breaks  in  two  or 
conductor's  valve  is  opened  to  stop  the  train  in  case  of 
accident,  the  brakes  will  operate  instantly  as  the  train  pipe 
pressure  can  be  reduced  from  the  train  faster  than  the 
running  position  feed  port  can  supply  it.  If  the  valve  is 
on  full  release  the  brakes  will  not  set  tight  till  the  main 
reservoir  pressure  is  also  reduced. 


H-5    BRAKE   VALVE  75 

33-  Q-  What  are  the  essential  differences  between 
the  1892  model  and  the  1906  or  H-5  brake  valve? 

A.  The  H-5  brake  valve  has  all  the  pipe  connections 
made  at  the  bottom  section  or  pipe  bracket,  so  the  valve 
can  be  removed  from  the  engine  without  disturbing  any 
pipe  joints.  The  feed  valve  is  located  on  a  pipe  between 
the  main  reservoir  and  brake  valve.  The  brake  valve 
receives  main  reservoir  air  direct  through  one  pipe.  This 
air  comes  on  top  of  the  rotary.  Air  at  a  reduced  pressure 
comes  through  the  feed  valve  and  another  pipe;  coming 
under  the  rotary  at  port  d.  The  preliminary  e  and  emer- 
gency exhaust  x  is  through  the  center  of  the  rotary  o  into 
the  cavity  EX  in  section  3  of  the  valve  and  thence  to  the 
atmosphere.  The  train  pipe  exhaust  is  at  the  bottom  and 
in  the  center  of  the  valve.  This  valve  is  intended  to  be 
used  in  connection  with  an  independent  brake  valve  and 
the  distributing  valve  for  the  locomotive  brake  and  has 
two  pipe  connections  for  this  purpose.  In  the  rotary  valve 
seat  there  is  a  port  /  that  connects  with  the  pipe  leading 
from  the  application  chamber  of  the  distributing  valve 
through  the  independent  brake  valve.  When  the  rotary 
is  in  running  position  port  h  in  the  rotary  registers  with  I, 
if  the  independent  valve  is  also  in  running  position,  the 
locomotive  brake  will  be  released. 

There  is  another  position  of  the  H-5  valve,  called  hold- 
ing position,  located  between  running  and  lap,  in  which 
port  h  does  not  register  with  port  I,  but  air  coming  through 
the  feed  valve  can  pass  out  of  d  through  f  in  the  face  of 
the  rotary  into  b,  thence  through  a  cored  out  passage  to 
c  and  the  brake  pipe  leading  to  the  train.  With  the  H-5 
valve  in  "  holding  position "  the  train  brake  will  be  re- 
leased and  the  locomotive  brake  held  set.  This  port  /  is 
also  lapped  in  full  release,  so  that  the  train  brake  can  be 
released  and  at  the  same  time  the  engine  brake  be  held 
set  if  required;  this  will  hold  the  slack  back  in  the  head 
end  of  the  train  and  make  it  safe  to  release  the  train  brake 
at  slow  speeds,  and  not  break  in  two.  Another  port  i  in 
the  rotary  seat  connects  with  the  double  heading  pipe,  port 


M/5  AUTOMATIC  BRAKE  VALVE 


H-5  BRAKE  VALVE  77 

h  registers  with  i  in  lap  position.  This  pipe  leads  from 
the  exhaust  port  of  the  distributing  valve  and  is  only  used 
on  the  following  engine  of  a  double  header.  When  the 
double  header  cut  out  cock  under  the  brake  valve  is  closed 
this  pipe  connection  through  the  cock  is  open. 

In  the  emergency  position  of  the  rotary,  port  /  in  the 
seat  registers  with  port  g  through  the  groove  n  in  the 
face  of  the  rotary  so  that  in  emergency  position  air  from 
the  brake  valve  reservoir  can  flow  into  application  chamber 
of  distributing  valve  and  apply  the  engine  brake  with 
greater  force.  Port  p  connects  with  the  excess  pressure 
head  of  the  pump  governor,  when  the  rotary  is  in  full  re- 
lease, running  or  holding  positions ;  main  reservoir  air 
can  pass  through  port  s  in  the  rotary  and  the  small  groove 
in  its  face  and  enter  port  p,  thus  controlling  the  excess 
pressure  head  of  the  governor  in  these  positions.  In  full 
release  main  reservoir  air  from  port  ^  flows  through  the 
warning  port  r  into  EX  and  gives  the  warning  that  the 
valve  is  in  full  release  position.  In  service  position  port  h 
in  the  rotary  registers  with  e  in  the  seat,  air  from  cham- 
ber D  flows  into  o  and  EX,  all  other  ports  in  the  seat 
are  closed.  The  action  of  the  equalizing  piston  15  has 
already  been  described.  Cavity  k  in  the  face  of  the  rotary 
connects  ports  g  and  ~c  in  running  and  holding  positions, 
so  that  train  pipe  and  chamber  D  charge  up  alike  in  these 
positions  and  there  is  no  flash  of  air  from  the  train  pipe 
exhaust  when  releasing  brakes  with  a  short  train. 

Plug  29  can  be  taken  out  and  some  good  oil  poured 
in  the  cavity  around  the  lower  edge  of  the  rotary  to  lubri- 
cate it.  Spring  30  holds  the  rotary  key  7  up  against  gasket 
8  when  there  is  no  air  pressure  to  do  this.  In  full  release 
position  main  reservoir  air  passes  through  ports  a  in  the 
rotary  and  directly  into  port  b  and  the  train  pipe,  and  port 
/  registers  with  the  equalizing  port  g  so  chamber  D  charges 
quickly.  In  running  and  holding  positions  cavity  f  in  the 
face  of  the  rotary  connects  ports  d  and  b  so  the  air  that 
has  been  reduced  in  pressure  at  the  feed  valve  can  flow 


78  THE    INDEPENDENT    BRAKE    VALVE 

into  the  train  pipe  and  charge  it  up  to  the  pressure  that 
the  feed  valve  closes  at,  and  no  higher.  To  take  the  H-5 
valve  off  its  pipe  bracket  take  out  the  through  bolts.  To 
take  the  valve  apart  take  out  the  tap  bolts  that  hold  the 
valve  sections  together. 

34.     Q.     Describe  the  independent  brake  valve. 

A.  This  valve  is  used  in  connection  with  the  distribut- 
ing valve  and  allows  air  to  flow  into  or  out  of  the  appli- 
cation chamber,  and  thus  operate  the  supply  valve  piston, 
that  in  turn  operates  the  valves  which  admit  main  reser- 
voir air  to  the  brake  cylinder  to  set  the  engine  brake  or 
exhausts  the  cylinder  air  to  release  it.  It  does  not  admit 
main  reservoir  air  direct  to  the  brake  cylinder  as  the 
Straight  Air  brake  valve  does.  It  has  four  positions,  re- 
lease, running,  lap  and  service,  that  come  the  same  a»  on 
the  automatic  brake  valve.  A  stiff  spring  9,  in  the  top  of 
the  valve  body  3  returns  the  handle  from  release  to  run- 
ning position  as  soon  as  the  engineer  removes  his  hand. 

In  running  position  port  d  from  the  distributing  valve 
is  connected  through  port  f  in  the  rotary  5  with  port  c 
leading  to  the  automatic  valve,  so  that  air  can  flow  from 
the  application  chamber  through  the  independent  valve  to 
the  automatic  brake  valve,  and  this  valve  should  always 
be  in  running  position  when  the  automatic  valve  is  to 
operate  the  engine  brake.  In  release  position  cavity  g  in 
the  face  of  the  rotary  5  connects  port  d  with  the  exhaust 
port  h  in  the  center  of  the  seat,  so  that  the  application 
chamber  air  can  pass  to  the  atmosphere  without  regard  to 
the  position  of  the  automatic  brake  valve  and  release  the 
engine  brake  independently  of  the  train  brake.  In  service 
position  cavity  e  in  the  rotary  connects  the  supply  port  b 
with  d  so  that  main  reservoir  air  reduced  to  45  pounds  can 
flow  direct  to  the  application  chamber  and  operate  the  dis- 
tributing valve  supply  piston;  this  position  applies  the 
engine  brake  independently.  Lap  position  blanks  all  ports 
and  is  to  be  used  only  when  making  a  graduated  applica- 
tion or  release  of  the  engine  brake  or  when  trying  to 


THE    INDEPENDENT    BRAKE   VALVE 


79 


'STPiBt-'TiHG  YAtVt 


prevent  the  re- 
lease of  the  en- 
gine brake  by  the 
automatic  valve, 
or  the  passage  of 
air  from  the 
brake  valve  res- 
e  r  v  o  i  r  through 
the  automatic 
valve  in  the  em- 
ergency position 
to  the  application 
chamber.  Leav- 
ing the  indepen- 
dent valve  in  lap 
position  when  op- 
erating the  auto- 
matic valve  i  s 
liable  to  cause 
trouble.  This 
valve  does  not 
affect  the  opera- 
tion of  the  train 
brake  in  any  way 
and  is  to  be  used 
when  operating 

the  engine  brake  while  switching  cars,  or  independently 
at  any  time.  Its  supply  of  air  comes  from  the  main  reser- 
voir through  a  reducing  valve  set  at  45  pounds.  The 
arrangement  of  these  valves  is  shown  in  the  page  illus- 
tration and  they  are  part  of  the  ET  locomotive  brake 
equipment.  The  location  of  each  valve  in  this  type  of 
brake  is  plainly  shown,  so  no  description  is  given. 

35.     Q.     Describe    the    distributing    valve    in    its    con- 
struction and  operation. 

A.    The    distributing   valve    is    shown    separately    and 
attached  to  its  double-chambered  reservoir.     The  pressure 


INTERIOR  VIEWS  OF  THE  INDEPEND 
-ENT  BRAKE  VALVE 


THE  DISTRIBUTING   VALVE 


8l 


chamber  represents  an  auxiliary  reservoir  and  the  applica- 
tion chamber  the  brake  cylinder;  there  are  five  pipe  con- 
nections, only  two  of  which  show  on  the  exposed  side  of 
the  reservoir.  On  the  next  page  is  shown  a  diagrammatic 


view  of  the  valve  and  reservoir,  in  which  the  valve  is 
shown  much  larger  in  proportion  to  the  size  of  the  reser- 
voir than  it  really  is.  We  will  use  capital  letters  as  ab- 
breviations for  the  names  of  the  five  pipe  connections  made 
to  the  reservoir  and  from  there  to  the  various  parts  of  the 


/ 

V 

' 
-•' 

\ 

APPLI- 
CATION 

; 

PRESSURE 

CHAMBER 

'•^ 

CHAMBER 

/ 
/. 

y 

RELEASE,  AUTOMATIC  OR 
INDEPENDENT 


THE   DISTRIBUTING   VALVE  83 

valve.  In  the  diagrammatic  view  the  slide  valve  31  and 
graduating  valve  28  are  shown  both  above  and  below  the 
piston  stem  26,  so  the  ports  that  are  beside  each  other  can 
be  seen.  Air  from  the  main  reservoir  enters  at  supply, 
passes  through  port  a  up  and  around  the  application  valve 
5 ;  also  down  to  the  seat  of  slide  valve  31  and  through 
port  n  to  the  pressure  chamber  when  valve  31  is  in 
emergency  position.  Air  from  the  brake  pipe  enters  at 
BP  and  is  on  the  outside  of  equalizing  piston  26.  When 
this  piston  is  in  release,  as  shown,  train  pipe  air  can  pass 
around  the  piston  through  the  feed  port  into  the  pressure 
chamber.  When  the  train  pipe  pressure  is  reduced  piston 
26  moves  back  towards  the  reducing  train  pipe  pressure, 
bringing  first  the  graduating  valve  28  and  then  moving 
the  slide. valve  31  as  soon  as  the  lost  motion  between  the 
shoulders  on  piston  stem  and  valve  31  is  taken  up.  This 
admits  air  from  the  pressure  chamber  to  the  application 
chamber  through  ports  o  and  h,  and  in  this  respect  is 
exactly  like  a  triple  valve  when  feeding  air  from  the 
auxiliary  to  the  brake  cylinder.  With  a  partial  application 
of  the  automatic  brake  the  equalizing  piston  26  and  its 
valves  reduces  the  pressure  in  the  pressure  chamber  by 
allowing  air  to  pass  into  the  application  chamber  till  the 
pressure  chamber  is  a  trifle  lower  than  the  train  pipe,  when 
piston  26  moves  back  and  laps  graduating  valve  28.  This 
movement  has  been  fully  explained  in  connection  with  the 
triple  valve. 

At  the  same  time  that  air  flows  into  the  pressure 
chamber  or  dummy  brake  cylinder,  it  also  flows  up  through 
port  h  into  the  space  g  behind  the  application1  piston  10. 
If  the  brake  is  "  creeping  on  "  and  air  flows  into  g  slowly 
it  may  pass  through  leakage  port  between  g  and  b,  thence 
to  the  atmosphere  through  exhaust  ports  e  and  d.  This 
leakage  port  is  omitted  in  the  later  valves.  But  during 
a  brake  application  air  from  o  passes  into  h  and  g  much 
faster  than  it  can  get  through  leakage  port,  so  that  the 
pressure  in  g  will  move  piston  10  to  the  right.  This  moves* 
application  valve  5  and  as  soon  as  the  lost  motion  is  taken 


»4  THE   DISTRIBUTING   VALVE 

up,  exhaust  valve  16  covers  the  exhaust  ports  e  and  d. 
Valve  5  next  opens  the  supply  port  from  a  into  b  and  c, 
so  main  reservoir  air  can  flow  to  the  brake  cylinder  at  BC 
and  apply  the  brake.  We  will  suppose  a  7  pound  reduction 
is  made  in  the  train  pipe.  As  soon  as  it  is  felt  on  the 
piston  26  at  p  it  will  move  towards  BP,  open  valves  28 
and  31  and  closing  exhaust  port  k.  Air  will  flow  into  the 
application  chamber  and  cavity  g  till  the  pressure  cham- 
ber or  dummy  auxiliary  is  also  reduced  7  pounds,  when 
piston  26  will  lap  valve  28  over  the  port  in  valve  31. 
Air  pressure  in  g  will  then  move  piston  10  and  its  valves 
5  and  16,  closing  the  exhaust  ports  c  and  d  and  opening 
supply  port  from  a  to  c.  To  open  port  from  a  the  gradu- 
ating stem  19  must  be  moved  back  against  the  tension  of 
its  spring  20,  when  the  stem  19  meets  cap  nut  22.  As 
soon  as  the  pressure  in  b  and  the  engine  brake  cylinders 
is  equal  to  that  in  g  on  the  other  side  of  piston  10;  spring 
20  and  the  stem  19  will  move  piston  10  and  valve  5  back 
to  lap,  but  does  not  move  valve  16  to  open  the  exhaust. 
This  applies  the  brake  and  holds  it  applied  as  long  as  any 
pressure  remains  in  g  and  h.  If  leaks  in  the  brake  cylinder 
packing  or  piping  reduce  the  pressure  in  b ;  piston  10  will 
move  towards  this  decreasing  pressure  and  open  the  sup- 
ply port  till  the  pressure  in  the  cylinder  again  equals  that 
in  g,  when  piston  10  will  lap  valve  5.  When  the  air  in 
the  application  chamber  is  either  wholly  or  partly  ex- 
hausted to  the  atmosphere  piston  10  will  be  moved  back 
towards  g  by  the  brake  cylinder  pressure  and  either  wholly 
or  partly  exhaust  the  air  from  the  cylinder. 

In  the  independent  application  and  release  of  the 
brake  through  the  distributing  valve  the  lower  or  equal- 
izing piston  26  and  its  valves  do  not  move.  The  air  is  fed 
into  and  out  of  the  application  chamber  and  chamber  g 
by  the  independent  brake  valve  at  the  pipe  connection  AC. 
This  air  comes  from  the  main  reservoir  and  is  reduced  to 
45  pounds  pressure  before  passing  through  the  independent 
brake  valve.  When  the  independent  valve  is  in  service 
position  air  flows  in  at  AC  till  the  pressure  in  the  appli- 


THE   DISTRIBUTING   VALVE  85 

cation  chamber  and  g  is  enough  to  apply  the  brake  the 
desired  amount.  A  partial  or  full  application  can  be  made 
depending  on  how  much  air  is  admitted  through  the  brake 
valve,  and  a  partial  or  full  release  by  lapping  the  brake 
valve  before  all  the  air  has  escaped.  To  prevent  the  air 
passing  out  the  exhaust  port  k  of  valve  31  when  in  re- 
lease position  port  i  is  piped  at  DH  to  the  double  heading 
cock  in  the  train  pipe  under  the  automatic  brake  valve. 
When  this  cock  is  open  for  the  train  pipe,  as  it  should  be 
when  the  automatic  brake  is  being  operated  from  that 
engine,  the  pipe  leading  from  the  exhaust  port  k  is  closed 
so  no  air  can  escape  through  valve  31  when  in  release 
position.  But  if  this  engine  is  not  operating  the  train 
brake  in  a  double  header  the  exhaust  port  k  is  open 
through  a  pipe  from  DH  through  the  cut-out  cock  and  a 
port  in  the  H-5  automatic  brake  valve  when  the  rotary 
is  in  lap  position. 

There  is  a  cut-out  cock  in  the  train  pipe  connection 
before  reaching  BP  to  cut  out  the  distributing  valve  from 
operating  automatically  when  necessary.  Closing  this  cut- 
out cock  does  not  prevent  the  brake  being  operated  by 
the  independent  brake  valve. 

When  the  automatic  brake  valve  is  in  the  emergency 
position  air  from  the  brake  valve  reservoir  can  flow 
through  the  independent  valve — if  it  is  in  running  position 
— into  the  application  chamber  and  g,  so  that  the  engine 
brake  can  be  applied  in  that  position  of  the  automatic 
valve,  even  if  cut  out  from  the  train  pipe. 

When  piston  26  is  moved  its  full  travel  to  the  emer- 
gency application  position  so  it  rests  against  gasket  25  in  cap 
23;  ports  n  in  the  bushing  and  m  in  valve  31  will  be  open  to 
each  other  so  main  reservoir  air  can  flow  slowly  through 
the  small  port  n  into  the  pressure  chamber  and  increase 
the  pressure  there.  At  the  same  time  port  /  is  open  to  the 
safety  valve  34  and  it  will  reduce  the  pressure  there  to 
about  60  pounds.  This  feature  is  intended  to  operate  the 
brake  the  same  as  the  high  speed  reducing  valve.  In  the 
No.  5  distributing  valve  (the  one  here  described),  port  /  is 


86  THE  SAFETY  VALVE" 

only  open  to  the  pressure  chamber  and  port  h  in  applica- 
cation  position;  being  closed  in  release  and 
lap  positions  of  valve  28  and  31.  For  this 
reason,  when  using  the  independent  brake 
valve  only  with  the  equalizing  piston  26  in 
release  or  lap  the  safety  valve  34  will  not 
reduce  the  pressure  in  the  application  cham- 
ber should  the  reducing  valve  for  the  inde- 
pendent valve  be  out  of  order  and  allowing 
too  high  a  pressure.  This  safety  valve  is  set 
at  53  pounds,  and  will  blow  down  to  that  with 
^.-SAFETY  VALVE  an  automatic  service  application. 

If  you  will  remember  that  the  distributing  valve  de- 
pends on  the  pressure  of  air  in  the  application  chamber  to 
open  and  close  the  valves  that  control  the  passage  to  and 
from  the  brake  cylinder  it  will  make  the  operation  of  this 
valve  clear  to  you.  When  air  gets  into  this  chamber, 
whether  from  a  leak  through  either  brake  valve  or  the 
slide  valve  31,  it  will  raise  the  pressure  there  and  apply 
the  engine  brake.  Or,  if  the  air  can  pass  out  of  this 
chamber  either  the  regular  way  through  the  brake  valves 
or  leaks  in  the  pipe  connections  the  engine  brake  will  re- 
lease. First  study  out  how  the  air  gets  into  and  out  of  this 
chamber  and  it  will  clear  up  many  things  that  otherwise 
would  puzzle  you. 

There  are  several  forms  of  the  distributing  valve  in 
service,  with  some  differences  in  their  construction  and 
operation,  and  it  is  likely  that  other  changes  will  be  made 
in  the  No.  5  valve  from  time  to  time. 

36.  Q.  Describe  the  Combined  Automatic  and  Straight 
Air  Engine  and  Tender  brake. 

A.  This  brake  valve  contains  two  check  valves,  8  and 
9 — see  Figures  i  and  2 — to  admit  air  from  the  main  reser- 
voir to  the  brake  cylinders  and  9  to  exhaust  the  air  from 
the  cylinders  to  the  atmosphere.  These  valves  are  moved 
away  from  their  seats  alternately  by  the  shaft  2,  which 
when  revolved  to  the  right,  forces  valve  8  off  its  seat 
against  the  pressure  of  the  main  reservoir  air  in  a  and  the 
spring  ii ;  when  revolved  to  the  left  forces  the  exhaust 


THE    STRAIGHT   AIR   BRAKE   VALVE  57 

valve  9  off  its  seat  against  the  pressure  of  the  spring  10  and 
the  brake  cylinder  air.  To  apply  the  brake  the  handle  4 
is  moved  to  the  right.  With  valve  8  moved  down  off  its 
seat,  main  reservoir  air  in  a  passes  through  b,  bl  and  b2 
— see  Fig.  3 — and  out  at  x — see  Fig.  2 — through  the  pip- 
ing leading  to  the  Double  Check  valves  and  cylinders. 
Exhaust  valve  9  at  this  time  is  on  its  seat  as  shown  in  Fig. 


Fic.l. 


STRAIGHT-AIR  BRAKE  VALVE. 


Fic.3. 


2,  so  that  no  air  can  pass  out  through  c  to  the  exhaust. 
To  release  the  brake  the  handle  4  is  moved  to  the  left, 
which  allows  main  reservoir  air  valve  8  to  close  and  then 
opens  exhaust  valve  9,  so  that  air  in  the  cylinders  can  pass 
out  to  the  atmosphere.  When  handle  4  is  in  mid-position, 
both  valves  are  closed  so  that  they  are  "  on  lap." 

A  leather  washer  6  prevents   leakage   from   b   to   the 


88  THE    DOUBLE    CHECK    VALVE 

atmosphere  when  the  brake  is  applied;  spring  7  holds 
shaft  2  against  this  washer  when  there  is  no  compressed 
air  in  this  part  of  the  valve — see  Fig.  3. 

To  regulate  the  pressure  of  the  air  feed  from  the  main 
reservoir  to  this  valve,  a  G-6  Slide  Valve  Feed  Valve  is 
used,  located  on  the  pipe  between  the  reservoir  and  brake 
valve  and  set  to  close  at  45  pounds.  This  reducing  valve 
regulates  the  brake  cylinder  pressure  to  the  proper  amount, 
and  also  restricts  the  flow  of  air  and  assists  the  engineer 
in  making  moderate  applications. 

The  Double  Check  Valve  shown  in  Fig.  4  is  located  in 
the  pipe  between  the  triple  valve  and  the  cylinders,  in  a 
horitzontal  position  so  that  it  will  not  open  or  close  by 
gravity.  The  triple  valve  is  coupled  to  one  end,  the 
straight  air  brake  valve  at  the  other.  The  brake  cylinder 
can  be  coupled  to  either  side,  as  shown,  one  side  can  be 
used  for  the  safety  valve,  or  a  driver  brake  cylinder  can  be 
coupled  to  each  side  and  the  safety  valve  located  in  the  pipe 
leading  to  the  cylinder.  Two  of  these  valves  are  required, 
one  on  the  engine  and  one  on  the  tender,  with  a  24  inch  pipe 
connecting  them  to  the  straight  air  brake  valve,  the  same 
as  the  one  inch  train  pipe  connects  the  triple  valve  and 
automatic  brake  valve. 

Two  safety  valves  are  required,  one  for  the  engine  and 
one  for  the  tender,  set  at  53  pounds. 

When  the  straight  air  is  used  it  moves  valve  5,  Fig.  4, 
over  so  gasket  7  makes  a  tight  joint  at  b  and  the  air  passes 
through  opening  c  to  the  cylinders,  but  cannot  get  to  the 
exhaust  port  of  triple  valve.  If  automatic  is  applied,  air 
from  the  triple  valve  moves  valve  5  so  the  opposite  gasket 
makes  a  joint  at  a  and  air  passes  through  ports  c1  to  the 
cylinders  but  cannot  pass  to  the  straight  air  brake  valve. 
Thus  you  see  the  double  check  valves  automatically  con- 
nect the  brake  cylinders  to  either  the  automatic  or  straight 
air  system  and  prevent  air  passing  out  of  the  exhaust  port 
of  one  system  while  the  other  is  being  operated. 

When  operating  the  straight  air,  move  handle  4  over 
and  you  will  feel  the  resistance  of  valve  8;  a  little  practice 


OPERATING   THE    STRAIGHT    AIR    BRAKE  &) 

will  enable  you  to  calculate  the  amount  of  air  you  allow  to 
pass  into  the  cylinders  in  a  partial  application ;  you  can 
follow  up  by  admitting  additional  amounts  of  air,  till  if 


TO  BRAKE  CYLINDER, 
OR    FOR  SAFETY  VALVE 

Fig.  4 


Fig.  3 

necessary,  the  brake  is  fully  applied,  of  course  taking  care 
not  to  shock  the  cars  attached  to  the  engine  by  too  sud- 
den an  application.  If  it  is  to  be  held  fully  applied  leave 


9°  OPERATING    THE    STRAIGHT    AIR    BRAKE 

the  valve  in  application  position,  so  as  to  feed  up  any  leaks 
that  may  reduce  the  power.  For  a  full,  quick  application 
the  valve  may  be  opened  wide,  as  the  reducing  valve  will 
stop  the  flow  of  air  from  the  main  reservoir  when  it  reaches 
the  pressure  at  which  the  reducing  valve  is  set.  A  partial 
release  can  be  obtained  by  opening  and  closing  the  valve  9; 
a  quick,  full  release  by  moving  handle  4  to  exhaust  position 
and  holding  valve  9  open. 

If  the  straight  air  brake  is  left  on  lap  while  the  auto- 
matic is  applied,  when  the  automatic  is  released  the  double 
check  valve  may  be  shifted  by  the  pressure  of  the  air  that 
may  get  in  the  pipe  between  the  check  and  the  straight 
air  valve,  if  the  check  valve  shifts  and  closes  the  opening 
at  b  the  brake  cylinder  air  cannot  get  out  of  exhaust  port 
of  triple,  and  thus  cause  the  driver  and  tender  brakes  to 
stick.  A  new  style  of  doublecheck  valve  now  in  service 
prevents  this  trouble.  When  using  automatic,  handle  4 
should  always  be  in  full  release  position,  holding  valve  9 
open.  The  automatic  brake  valve  when  not  in  use  should 
be  on  running  position  and  at  least  10  pounds  excess 
carried  to  prevent  triple  valves  "  creeping  on  "  at  any  time. 

Never  apply  both  brakes  at  once  while  switching. 
When  you  use  automatic  be  sure  the  other  is  in  release 
position  first.  If  necessary  to  use  straight  air  on  top  of 
the  automatic  to  hold  the  slack  of  train,  when  the  auto- 
matic is  to  be  released,  remember  that  a  movement  of  both 
valves  to  release  is  necessary  to  let  off  the  locomotive 
brake. 

If  wheels  skid  on  a  good  rail,  test  the  safety  valves  and 
the  reducing  valve;  they  should  relieve  any  over  pressure, 
whether  from  a  reducing  valve  allowing  too  high  a  pres- 
sure, of  from  a  "  double  application  " ;  that  is,  an  applica- 
tion with  the  automatic  while  the  straight  air  is  still  ap- 
plied ;  this  will  give  a  higher  pressure  than  if  the  automatic 
has  set  full  first  and  is  almost  sure  to  slide  wheels;  there- 
fore must  not  be  used.  Straight  air  gives  45  pounds  only 
in  the  cylinders  at  any  time;  if  the  automatic  is  applied  on 
top  of  this  45  pounds,  the  70  pounds  in  the  auxiliary  will 


POSITION  OF  VALVE  BACKING  UP  91 

tend  to  raise  the  cylinder  pressure  close  to  65  pounds.    The 
safety  valves  should  reduce  it  down  to  53  pounds. 

Both  safety  valves  and  the  feed  valve  should  be  tested 
at  regular  intervals  with  a  gage  to  insure  that  they  regulate 
the  pressure  properly.  There  should  be  Tees  so  located  in 
the  pipes  that  a  gage  can  be  readily  attached  for  this 
purpose. 

37.  Q.     How    should    the    automatic    brake    valve    be 
carried  when  backing  up  the  train,  or  when  expecting  the 
train  men  to  set  brake  from  rear  end? 

A.  On  running  position;  so  the  brake  will  be  applied 
as  soon  as  train  pipe  pressure  is  reduced,  when  brake 
valve  should  be  placed  on  lap  at  once.  This  also  applies 
to  pushing  a  snow  plow  if  brake  is  handled  from  the  plow. 
A  few  companies  require  that  the  brake  valve  be  kept  on 
running  position  all  the  time,  when  backing  up  a  train. 
There  is  some  difference  of  opinion  as  to  the  proper  po- 
sition of  the  H-5  valve,  some  carry  it  on  holding  position 
and  use  the  independent  valve  to  release  the  locomotive 
brake. 

38.  Q.     How   do   you    set   and   release   the   automatic 
brake? 

A.  Reducing  the  train  pipe  pressure  operates  the  triple 
valve  to  apply  the  brake  and  restoring  the  original  pres- 
sure releases  it;  this  is  the  engineer's  method.  It  can  be 
applied  from  the  train  by  opening  the  conductor's  valve,  or 
the  angle  cock  at  the  rear  of  last  air  brake  car.  Pulling 
the  hose  apart  at  the  couplings,  a  hose  bursting  or  any 
bad  leak  or  break  in  the  train  pipe  will  set  the  brake. 
When  the  train  breaks  in  two  between  air  cars  all  air 
brakes  on  both  parts  of  the  train  that  are  cut  in  set  in- 
stantly. A  brake  can  be  set  on  a  car  that  is  alone  by  open- 
ing the  angle  cock  to  let  air  out  of  the  train  pipe.  In  such 
a  case  the  brake  can  be  released  by  bleeding  the  auxiliary 
reservoir.  If  a  brake  is  to  be  released  from  the  train  the 
auxiliary  pressure  is  reduced  by  bleeding  till  it  is  lower 
than  the  train  pipe  so  the  triple  valve  will  open  the  exhaust 
port,  or  all  the  air  is  bled  out  of  both  reservoir  and  brake 
cylinder. 


92  GRADUATED   APPLICATION 

39.  Q.     Can    a    gradual    application    of   the    brake    be 
made,  that  is,  with  only  part  of  its  full  force? 

A.  Yes,  by  reducing  the  train  pipe  pressure  only  a  few 
pounds,  say  five  to  seven  pounds  for  first  reduction ;  this 
reduction  is  necessary  to  make  brake  piston  move  over 
leakage  groove ;  a  lighter  reduction  than  five  pounds  will 
not  always  do  this ;  two  to  three  pounds  at  each  of  the 
succeeding  reductions,  less  than  twenty  pounds  in  all. 

40.  Q.     Why  does  this  reduction  of  only  a  few  pounds 
in  the  train  pipe  pressure  make  a  light  application  of  the 
brake  ? 

A.  '  With  a  light  reduction  the  triple  piston  moves  down 
slowly,  opening  the  air  valve  slowly;  the  air  from  the 
auxiliary  reservoir  passes  into  brake  cylinder  through 
graduating  valve  and  a  small  port  in  the  slide  valve;  as 
soon  as  the  auxiliary  pressure  is  a  little  lower  than  train 
pipe  pressure,  the  train  pipe  pressure  raises  the  piston, 
closing  the  graduating  valve  so  no  more  air  can  pass  into 
brake  cylinder,  thus  setting  the  brake  lightly.  To  illus- 
trate this,  we  will  let  out  seven  pounds  of  air,  reducing" 
train  pipe  pressure  from  seventy  to  sixty-three  pounds, 
that  leaves  seventy  pounds  above  triple  piston,  which  moves 
the  triple  piston  down  towards  the  lower  pressure,  opening 
graduating  valve  7  first;  then  moving  slide  valve  3  so  that 
air  can  pass  through  it;  when  enough  air  has  gone  into  the 
cylinder  to  reduce  the  auxiliary  pressure  below  sixty-three 
pounds,  the  train  pipe  pressure  moves  the  piston  towards 
the  lower  auxiliary  pressure,  closing  graduating  valve; 
another  reduction  produces  the  same  effect,  each  time 
setting  brake  tighter  till  pressures  equalize.  The  piston 
moves  the  main  slide  valve  at  the  first  reduction,  but  only 
opens  and  closes  the  graduating  valve  at  the  following 
reductions  till  a  full  application  is  made. 

41.  Q.     How  much  do  you  reduce  the  train  pipe  pres- 
sure to  make  a  full  service  application  of  the  brake  if  the 
piston  travels  are  the  proper  length? 

A.  About  twenty  pounds,  or  from  seventy  pounds 
down  to  fifty,  or  until  the  auxiliary  pressure  has  equalized 
with  brake  cylinder. 


FULL  APPLICATION  93 

42.  Q.  Why  does  a  reduction  of  twenty  pounds  set 
the  brake  "  full  on  "  ? 

A.  If  the  brake  is  in  good  order,  with  a  piston  travel 
of  eight  inches,  a  reservoir  pressure  of  seventy  pounds  will 
fill  the  brake  cylinder  and  equalize  in  both  at  fifty  pounds, 
that  will  leave  fifty  pounds  on  top  of  triple  piston.  If  the 
pressure  on  the  train  pipe  side  or  under  the  triple  piston 
is  any  less  than  fifty  pounds,  the  piston  will  stay  down 
and  hold  the  air  valve  open  and  pressures  must  equalize. 
One  pound  less  will  hold  it  down  as  well  as  any  amount. 
When  it  has  equalized,  no  more  air  will  pass  from  aux- 
iliary to  brake  cylinder,  pressure  on  brake  piston  will  not 
rise  above  fifty  pounds,  and  brake  cannot  be  set  tighter. 
Any  reduction  of  train  pipe  pressure  that  leaves  it  lower 
than  auxiliary  pressure  will  set  the  brake  tight.  If  a  re- 
duction of  twenty  pounds  opens  the  air  valve  and  holds  it 
open,  any  further  reduction  will  not  produce  any  effect  on 
it,  and  so  far  as  that  brake  is  concerned  is  only  a  waste  of 
air  which  must  be  supplied  from  main  reservoir  when  you 
want  to  release  brake.  If  any  check  valves  in  quick  action 
triples  leak,  a  reduction  in  train  pipe  pressure  below  brake 
cylinder  pressure  will  let  the  brake  leak  off  through  this 
check  into  train  pipe. 

43-  Q-  What  is  necessary  to  have  brakes  set  alike, 
with  same  reduction  of  train  pipe  pressure  and  release  at 
same  time,  with  same  increase  of  train  pipe  pressure? 

A.  ist.  The  auxiliary  pressures  must  all  be  the  same 
to  move  triples  down  towards  the  same  reduced  train  pipe 
pressure.  For  example,  if  one  auxiliary  has  seventy 
pounds,  another  sixty,  a  reduction  of  train  pipe  pressure 
below  seventy  will  set  the  first  brake,  but  it  takes  a  reduc- 
tion of  below  sixty  to  set  the  other  one.  2d.  All  piston 
travels  must  be  the  same,  for  with  a  twenty  pound  reduc- 
tion a  short  travel  equalizes  at  a  less  reduction  with  a 
higher  pressure  than  a  long  travel.  When  train  pipe  pres- 
sure is  increased,  triple  controlling  brake  with  long  travel 
will  release  first  as  the  auxiliary  pressure  is  lowest.  Thus, 
brake  with  long  travel  equalizes  last  with  lowest  piston 


94  THE    PLAIN    TRIPLE    VALVE 

pressure  and  lets  go  first.  3d.  That  all  triples  and  brake 
pistons  are  in  good  order  and  no  leaks.  4th.  That  the 
main  reservoir  pressure  and  volume  are  sufficient  to  move 
all  triples  to  release  quickly. 

44.  Q.     What  is  the  difference  between  the  plain  engine 
triple  valve  and  the  car  or  quick-action  triple?     Why  will 
not  the  plain  triple  do  as  well  on  a  long  train? 

A.  A  plain  triple  gets  all  its  supply  of  air  to  set  the 
brake  from  the  auxiliary  reservoir  only;  the  quick-action 
triple  gets  it  all  from  the  auxiliary  on  a  service  application ; 
when  used  with  emergency  it  gets  air  from  both  train  pipe 
and  auxiliary.  With  a  long  train  equipped  with  plain 
triples  It  takes  some  seconds  to  reduce  the  train  pipe 
pressure  at  last  car  and  operate  the  last  triple;  the 
pressure  in  train  pipe  is  reduced  slowly  on  last  cars,  which 
makes  them  set  gradually;  the  train  pipe  reduction  is  made 
at  the-  engine  only.  The  quick  action  triple  has  two 
separate  actions;  in  one  a  service  application  operates  only 
the  plain  part  of  it;  in  the  other,  plain  and  quick  action 
parts  are  operated  at  once.  A  quick  action  triple  is  not 
always  needed  on  an  engine  or  tender,  as  they  are  so  close 
to  the  brake  valve  that  they  operate  quickly  enough.  In  an 
emergency  application  the  quick  action  triple  allows  some 
of  the  train  pipe  air  to  escape  at  the  triple  so  that  the  train 
pipe  pressure  is  suddenly  reduced  at  this  triple;  this  also 
operates  the  next  triple  quick-action,  which  reduces  the 
train  pipe  pressure  still  more,  so  that  all  the  triples  act 
quicker  than  when  the  reduction  is  made  at  the  brake 
valve,  and  all  the  brakes  are  set  at  nearly  the  same  instant. 
Thus  there  is  less  shock  to  the  rear  cars  of  a  full  air  brake 
train,  as  the  action  of  the  triples  travels  from  one  to  the 
other  faster  than  the  slack  can  run  up  from  car  to  car. 

45.  Q.     Describe  the  construction  and  operation  of  the 
Quick  Service  Triple  Valve. 

A.  The  quick  service  triple  valve  shown  in  the  next 
illustration  is  similar  to  the  ordinary  quick-action  triple 
in  use  for  many  years,  but  has  some  additional  features. 
There  is  an  additional  air  port  b  leading  from  the  chamber 


QUICK-SERVICE    TRIPLE    VALVE 


95 


Y  between  the  train  pipe  check  12  and  the  emergency  valve 
10,  up  through  the  triple  body  .to  the  slide  valve  bushing  at 
c.  This  port  c  is  covered  by  the  slide  valve  so  any  air 
passing  through  port  c  must  also  pass  through  a  port  in 
the  slide  valve  to  get  any  farther.  The  graduating  valve  7 
is  a  small  flat  valve  with  a  cavity  in  its  face,  this  valve 
rides  on  the  back  of  the  slide  valve  3  and  moves  each  time 
piston  4  does.  There  is  some  lost  motion  between  the 


27 


26 

shoulders  of  the  piston  stem  and  the  ends  of  slide  valve  3, 
so  the  piston  can  move  this  distance  without  moving  valve 
3,  this  allows  the  piston  to  move  and  close  the  feed  port  * 
as  well  as  open  and  close  the  ports  under  the  graduating 
valve  without  moving  slide  valve  3.  On  the  reservoir  end 
of  the  triple  is  attached  a  cage  29,  containing  a  "  retarded 
release "  stem  31  and  its  spring  33.  A  small  pin  34  pre- 
vents stem  31  moving  too  far  in  the  cage  when  taken  off. 
There  is  no  feed  groove  in  the  shoulder  of  piston  4  where 
it  rests  against  the  slide  valve  bushing  when  at  its  ex- 
treme travel  in  releease  position,  so  that  in  this  position, 
air  passing  through  feed  port  i  can  not  get  into  the  aux- 


g6  QUICK-SERVICE  TRIPLE   VALVE 

iliary.  When  the  piston  and  slide  valve  are  in  free  release 
position  the  stem  31  and  spring  33  are  in  normal  position — 
not  compressed — the  exhaust  port  in  slide  valve  3  is  wide 
open  and  the  feed  ports  open  so  train  pipe  air  can  equalize 
to  the  auxiliary.  In  the  triples  used  with  10  inch  brakes 
and  larger  ones,  there  is  also  a  feed  port  through  the  slide 
valve  that  is  open  in  free  release.  There  is  a  small  feed 
port  through  the  slide  valve  that  is  open  only  in  retarded 
release  position  which  charges  the  auxiliary  very  slowly. 
The  feed  port  i  around  the  piston  charges  the  auxiliary 
in  free  release  position  only,  and  is  the  same  size  in  all 
quick-service  triples,  as  most  of  the  air  in  the  large  triples 
passes  through  the  feed  port  through  the  slide  valve. 
After  the  auxiliary  has  charged  to  standard  pressure, 
which  we  will  assume  is  70  pounds,  a  moderate  train  pipe 
reduction  will  move  the  piston  4  to  the  right  following  the 
reduction.  This  movement  first  closes  feed  port  i  and 
moves  the  graduating  valve  7  on  the  back  of  the  slide 
valve  3  to  close  feed  port  and  open  the  supply  ports 
under  it.  The  slide  valve  then  moves  first  closing  the 
exhaust  port  and  next  opens  the  service  ports  in  valve 
3  to  the  ports  in  its  seat.  Auxiliary  air  then  flows 
to  the  cylinder  through  port  p.  At  the  same  time  train 
pipe  air  from  chamber  Y  flows  through  ports  b,  c,  the 
cavity  of  the  graduating  valve  7  and  ports  in  slide  valve 
3  into  port  t  in  the  seat,  and  thence  around  the  emergency 
piston — which  is  not  an  air  tight  fit — into  X  and  the  cylin- 
der. This  small  amount  of  train  pipe  air  passing  to  the 
cylinder  is  not  sufficient  to  cause  an  emergency  reduction; 
but  causes  the  next  triple  to  operate  more  certainly  and 
thus  applies  all  brakes  in  a  train  in  less  time  than  when 
the  entire  train  pipe  reduction  is  made  at  the  brake  valve. 
The  train  pipe  air  passing  to  the  cylinder  in  a  service  appli- 
cation increases  the  pressure  there  so  that  a  five  pound 
reduction  in  train  pipe  and  auxiliary  will  give  about 
fourteen  pounds  in  the  cylinder  as  well  as  applying  the 
quick-service  triples  in  less  time  from  front  to  rear  of 
train. 


QUICK-SERVICE    TRIPLE    VALVE  97 

On  account  of  the  arrangement  and  size  of  the  service 
ports  the  quick-service  triples  are  not  as  liable  to  go  into 
undesired  quick  action  as  the  older  form.  When  in  service 
position  the  ports  are  only  open  a  portion  of  their  full  size 
to  reduce  the  auxiliary  pressure  as  fast  as  the  train  pipe 
pressure  is  ordinarily  reduced  at  the  brake  valve.  If  the 
triple  piston  moves  over  enough  to  compress  the  graduating 
spring  22  the  service  ports  will  open  wide,  this  reduces 
auxiliary  pressure  so  fast  that  the  piston  will  not  go  to 
emergency  position  for  a  moderate  reduction  unless  it  is 
defective.  When  the  brake  valve  is  placed  in  full  release 
and  the  train  pipe  at  the  head  of  the  train  charged  much 
higher  than  the  auxiliary  pressures  there  the  quick-service 
triples  there  will  move  past  free  release  position  compress- 
ing the  stem  31  and  spring  33  and  the  slide  valve  exhaust 
cavity  will  be  moved  far  enough  so  the  wide  open  port  of 
this  cavity  will  be  beyond  the  exhaust  port  and  the  small 
part  of  the  exhaust  cavity  will  be  in  register  with  the  port. 
This  causes  the  air  to  exhaust  from  the  brake  cylinder 
very  slowly  and  the  quick-service  triples  at  the  head  end 
that  have  the  high  train  pipe  pressure  hold  their  brakes 
set  some  seconds  longer  than  when  in  free  release  position. 
As  the  train  pipe  pressure  reduces  farther  back  in  the  train 
until  it  is  not  enough  higher  than  the  auxiliary  to  move 
the  triple  piston  to  retarded  release  position  against  the 
resistance  of  spring  33,  the  triples  will  all  move  to  free 
release  position  as  fast  as  the  increase  of  train  pipe  pres- 
sure reaches  them.  On  a  fifty  car  train  equipped  with  the 
quick-service  triples,  about  one-third  of  them  or  fifteen  to 
twenty  will  go  to  retarded  release  and  those  next  will  re- 
lease quickly.  This  tends  to  release  the  middle  and  rear 
cars  of  a  long  train  before  the  cars  next  the  engine  are 
fully  released,  and  thus  prevent  the  slack  running  out  and 
breaking  trains  in  two  or  more  parts  when  releasing 
brakes  at  a  slow  speed.  To  get  the  full  value  of  the 
quick-service  triples  when  the  entire  train  is  not  equipped 
with  them,  these  triples  should  be  next  the  engine.  When 


98  EMERGENCY   APPLICATION 

at  the  rear  they  do  not  release  any  different  than  the 
ordinary  quick-action  triple. 

47.  Q.     What  is  the  emergency  or  quick  application? 
A.     If  the  train  pipe  pressure  is  suddenly  reduced  at 

the  first  application  ten  pounds  or  more,  at  the  quick- 
action  triple,  so  the  graduating  valve  cannot  reduce  the 
auxiliary  pressure  at  the  same  rate,  auxiliary  pressure 
will  move  piston  by  the  service  position,  the  emergency 
part  of  the  triple  valve  is  brought  into  action,  opening  a  large 
port  in  the  triple  so  the  air  goes  from  the  train  pipe  direct 
into  the  brake  cylinder,  not  only  setting  the  brake  quick- 
action  but  also  reducing  the  train  pipe  pressure  suddenly 
at  that  point,  instead  of  all  the  air  going  clear  to  brake 
valve  to  escape  and  reduce  pressure.  This  sudden  reduc- 
tion sets  the  next  triple  in  the  same  manner,  which  sets 
the  next  one,  and  so  on  to  the  last  car;  its  action  from 
one  car  to  another  is  so  quick  that  even  on  a  long  train  it 
seems  to  catch  all  at  once.  When  a  quick-action  triple 
takes  air  from  the  train  pipe  and  sets  the  next  triple 
quick-action,  it  also  takes  air  from  its  auxiliary  through 
a  small  port  s,  after  the  train  pipe  has  equalized,  so  the 
full  application  is  made  at  sixty  pounds,  about  ten  pounds 
more  than  the  piston  pressure  in  full  service  application. 

A  sudden  reduction  of  train  pipe  pressure  which  will 
pull  the  triple  piston  down  hard  enough  to  compress  the 
graduating  spring  and  let  piston  make  a  full  travel  will 
open  the  large  air  port  in  plain  triple  valve,  so  brake  will 
set  somewhat  quicker,  but  does  not  set  with  any  higher 
piston  pressure. 

48.  Q.     Explain  the  operation  of  the  quick-action  triple 
when  used  on  the  "  emergency." 

A.  A  sudden  reduction  in  the  train  pipe  pressure  right 
at  the  triple  must  be  made,  so  the  triple  piston  will  make 
a  full  stroke  and  open  the  emergency  port  in  seat  under 
slide  valve,  which  will  admit  the  auxiliary  pressure  over 
the  emergency  piston  8.  This  in  turn  pushes  the  emer- 
gency or  rubber-seated  valve  10  off  its  seat,  and  the  train 
pipe  air  can  then  go  direct  to  brake  cylinder  through  large 


EMERGENCY   APPLICATION 


99 


port  C,  raising  the  train  pipe  check  valve  15  to  do  this. 
As  soon  as  the  train  pipe  and  brake  cylinder  pressures 
have  equalized,  the  check  15  seats  itself,  and  a  spring  in 
this  check  valve  pushes  the  rubber-seated  valve  10  up 
against  its  seat  as  soon  as  the  auxiliary  and  brake  cylin- 


This  cut  shows  the  quick-action 
triple  in  emergency  position.    Port  / 
registers  with  thet  notch  in  side  of 
slide  valve  or  the  "removed  corner" 
of  slide  valve,  which  is  not  shown  in 
cut.      Auxiliary  air  passes   through 
this  notch  under  port  z  into  /  on  emergency 
piston  8.    Poits  z  and  /  are  beside  each  other, 
but  no  air  passes  from  port  z  into  t. 
• 
QUICK-ACTION  TRIPL.E  VAI«VE— EMERGENCY  POSITION. 

der  pressures  are  nearly  equalized.  At  the  same  time 
that  train  pipe  air  is  passing  into  the  cylinder,  the  air  from 
the  auxiliary  is  also  going  through  a  small  port  ya  the  end 
of  slide  valve  3.  This  port  is  made  very  small  to  give  the 
train  pipe  air  a  chance  to  equalize  into  the  brake  cylinder 


IOO  EMERGENCY  APPLICATION 

first,  then  the  auxiliary  pressure  equalizes  with  the  brake 
cylinder  afterward,  at  about  sixty  pounds.  The  emergency 
valve  10  is  used  to  hold  the  train  pipe  air  out  of  the  brake 
cylinder,  therefore  in  quick-action  it  must  be  moved  off  its 
seat  against  the  train  pipe  pressure ;  this  is  done  only  when 
triple  piston  makes  a  full  stroke  suddenly.  If  it  moves 
down  slowly,  the  graduating  valve  will  allow  air  to  pass 
from  auxiliary  into  brake  cylinder  before  emergency  port 
is  opened,  and  reduce  the  auxiliary  pressure  as  fast  as  the 
train  pipe  pressure  falls,  so  graduating  spring  will  have 
power  to  prevent  a  full  stroke  of  piston. 

49.  Q.     Can  you  get  the  emergency  action  of  the  quick- 
action  triple  while  brakes  are  set  with  a  service  applica- 
tion? 

A.  Not  unless  they  are  set  with  a  light  application. 
The  pressure  in  auxiliary  and  train  pipe  must  be  consider- 
ably higher  than  in  the  brake  cylinder,  or  the  emergency 
piston  will  not  move  valve  10  off  its  seat,  nor  will  check  15 
raise  to  allow  air  to  pass  through.  Then,  if  a  partial 
service  application  has  been  made,  the  graduating  valve 
can  open  first,  which  reduces  the  auxiliary  pressure  some 
and  retards  the  full  stroke  of  the  piston  a  little  in  opening 
the  emergency  port.  Even  if  all  these  emergency  valves 
operate  after  a  moderate  service  application,  only  a  very 
little  air  will  pass  through  them,  not  enough  to  affect  the 
triples  behind  it,  or  raise  the  pressure  in  cylinder  very 
much.  See  Q.  in. 

50.  Q.     Is  it  practicable  to  attempt  to  get  the  emer- 
gency action  of  the  brake  by  suddenly  recharging  the  train 
pipe  for  one  or  two  seconds  and  then  opening  the  direct 
application   port  wide? 

A.  No.  The  triple  piston  will  not  move  till  you  have 
reduced  the  train  pipe  pressure  a  little  lower  than  the 
auxiliary  pressure,  and  no  air  can  pass  into  the  brake 
cylinder  from  either  train  pipe  or  the  auxiliary  till  piston 
moves  and  opens  the  valves.  By  this  movement  you  will 
partially  release  some  of  the  brakes  and  get  a  lighter 
service  application  the  second  time  than  you  had  at  first. 


EMERGENCY  APPLICATION  IOI 

Don't  try  it.    Unless  you  have  time  to  recharge  auxiliaries 
to  seventy  pounds,  hang  on  to  what  you  have. 

51.  Q.     When   is   it   necessary   to   use   the   emergency 
application  ? 

A.  Only  in  case  of  accident,  or  sudden  danger  to  train 
or  persons. 

52.  Q.     Is  it  safe  to  try  and  retain  air  in  a  train  pipe 
in  the  emergency  application,  and  why  not? 

A.  It  is  not  safe  as  a  general  rule.  In  an  emergency 
when  life  or  property  are  in  danger,  you  must  act  quickly. 
The  point  is  to  get  stopped  dead  as  soon  as  possible,  and 
see  about  getting  started  afterwards.  An  emergency  appli- 
cation is  the  last  resort  and  you  must  get  it  when  you  need 
it.  If  you  do  not  let  nearly  all  the  air  out  of  a  long  train 
pipe,  some  of  the  triples  will  not  act  quick  enough.  If 
three  or  four  triples  are  cut  out,  or  there  are  three  or 
four  plain  triples  close  together  at  the  head  end  of  the 
train,  the  "  quick-action  "  will  not  catch  behind  them  and 
all  the  air  must  be  let  out  at  head  end  of  train  to  reduce 
the  pressure  as  quickly  as  possible.  A*  full  reduction  of 
twenty  pounds  is  necessary  to  set  the  plain  triples  on 
engine  and  tender  so  these  brakes  will  do  their  full  share. 
With  a  "  double  header "  it  is  generally  necessary  to  let 
the  air  out  at  brake  valve  of  rear  engine  to  catch  the  quick 
action  on  the  train.  With  a  full  train  of  quick  action 
triples  a  sudden  reduction  of  twenty-five  or  thirty  pounds 
at  the  engine  will  catch  them  all  and  leave  considerable 
air  in  the  train  pipe,  so  you  can  release  and  back  up  out  of 
the  other  train's  way  if  the  brake  stops  you  in  time.  This 
is  the  only  special  exception  to  the  general  rule.  It  is 
easy  to  hold  part  of  the  air  when  making  tests  or  in  the 
instruction  car;  but  when  you  think  some  one  is  going  to 
get  killed  it  is  not  quite  as  easy  as  "clear  over"  to  "full 
emergency." 

53.  Q.     How  does  the  quick  action  triple  operate  on  a 
short  train  if  graduating  pin  is  broken? 

A.  With  the  emergency  on  a  light  service  application. 
If  the  graduating  pin  is  broken,  the  graduating  valve  will 


IO2  DEFECTIVE   TRIPLE    VALVE 

be  held  on  its  seat  by  auxiliary  pressure,  and  the  emer- 
gency port  is  the  first  one  to  open. 

If  the  graduating  valve  is  gummed  up  or  dirty  so  the 
air  can  not  flow  past  it  properly,  the  triple  will  work  with 
emergency  when  you  make  a  moderate  service  application. 
With  a  long  train  the  emergency  port  is  opened  so  gradu- 
ally that  the-  air  can  get  past  the  emergency  piston  and  go 
to  the  cylinder  without  moving  the  emergency  piston. 

54.  Q.  If  while  making  a  moderate  service  applica- 
tion your  brakes  would  "  fly  on  "  and  at  the  same  time  the 
air  would  stop  running  for  a  moment  from  train  pipe 
exhaust  and  then  begin  again,  where  would  you  look  for 
the  trouble? 

A.  In  one  of  the  quick  action  triples.  This  action  of 
the  brake  valve  shows  that  one  of  the  triples  is  working 
quick  action  only,  in  advance  of  the  rest,  even  with  a 
service  application.  When  the  triple  works  quick  action, 
it  takes  some  air  from  the  train  pipe,  reducing  the  pressure 
so  the  equalizing  piston  seats  for  an  instant.  At  the  same 
time  the  black  Hand  takes  a  sudden  drop  for  an  instant. 
Probably  the  graduating  pin  is  broken,  although  a  broken 
graduating  pin  in  service  is  very  rare.  If  the  graduating 
spring  22  has  been  left  out  it  is  very  apt  to  cause  quick 
action.  If  the  triple  piston  or  slide  valve  is  gritty  or  badly 
gummed  so  it  does  not  move  freely,  it  will  cause  this 
trouble. 

If  the  graduating  valve  or  its  ports  are  gummed  up  so 
that  the  air  cannot  flow  past  it  out  of  auxiliary  to  equalize 
the  pressures  as  fast  as  it  flows  out  of  train  pipe,  this  triple 
will  be  sure  to  work  quick  action.  A  quick  action  triple 
that  needs  cleaning,  or  has  the  graduating  ports  defective 
in  any  way,  is  liable  to  work  quick  action  with  a  moderate 
service  reduction.  If  the  train  pipe  exhaust  elbow  is  gone 
from  the  brake  valve  it  will  allow  so  sudden  reduction  of 
train  pipe  pressure  that  the  triples  will  work  quick  action 
on  a  very  short  train. 

To  locate  one  of  these  defective  triples,  close  some  of 
the  angle  cocks  so  as  to  use  not  over  ten  cars  at  a  time, 


LOCATING  A   DEFECTIVE  TRIPLE  IO3 

and  make  a  moderate  reduction,  say  five  pounds,  then  make 
another  of  five  more.  If  the  brakes  work  quick  action  you 
can  be  certain  the  defective  triple  is  on  one  of  these  cars. 
After  recharging  set  the  brake  again  with  about  seven 
pounds  reduction,  and  note  which  brake  has  not  set  at  all. 
Cut  this  one  out  and  make  another  test  which  will  show  if 
you  have  the  right  one.  If  you  do  not  find  it  in  the  first 
set  of  ten  cars  tried,  cut  in  some  more  and  try  them.  The 
disabled  triple  will  not  always  set  at  the  first  reduction, 
and  will  work  quick  action  at  the  second  one;  it  is  more 
apt  to  give  trouble  in  a  short  train  than  in  a  long  one. 

55.  Q.     If  with  a  quick  action  triple,  the  brake  should 
refuse  to  release,  but  kept  blowing  from  the  exhaust  port 
or  pressure  retainer,  what  would  be  the  matter  and  what 
would  you  do? 

A.  The  emergency  valve  10  was  likely  held  off  its 
seat  or  was  worn  out  and  leaked  badly.  If  out  on  the  road 
and  valve  would  not  quit  leaking  after  a  few  emergency 
applications,  would  cut  out  that  brake.  If  the  gasket  be- 
tween the  triple  valve  and  cylinder  head  on  a  passenger 
brake  or  next  the  reservoir  on  a  freight  brake  had  blown 
out,  it  would  let  auxiliary  reservoir  air  into  exhaust  and  the 
blow  would  soon  be  down  to  the  capacity  of  the  feed  port 
in  triple  valve.  A  small  leak  past  the  emergency  valve 
when  the  brake  is  set  will  soon  equalize  the  brake  cylinder 
and  train  pipe  pressures.  With  a  sticky  triple  this  brake 
might  not  release  with  increase  of  train  pipe  pressure  and 
wheels  be  skidded.  Better  cut  out  such  a  brake  and  bleed 
it. 

56.  How    do    you    locate    a    leak    that    lets    off    the 
brake  ? 

A.  If  it  leaks  off  through  piston  packing  leather  the 
air  will  blow  out  of  the  hole  in  spring  case  or  lower  head 
in  push  down  brake;  with  a  pull  up  brake,  around  piston 
rod  or  through  the  vent  hole  in  top  head.  A  leaky  train 
pipe  check  valve  15  will  let  the  air  out  of  brake  cylinder 
into  the  train  pipe,  but  only  when  train  pipe  pressure  is 
lower  than  cylinder  pressure.  This  will  be  the  case  when 


104  TESTING   FOR    LEAKS 

hose  bursts  or  train  breaks  in  two,  or  engineer  reduces  the 
train  pipe  pressure  too  much.  In  ordinary  service  stops, 
leaks  at  this  point  do  not  affect  the  work  of  the  brake. 

A  test  for  leaky  train  pipe  check  valve  15  in  the  quick 
action  triples  can  be  made  at  the  brake  valve.  Reduce  the 
pressure  twenty  or  twenty-five  pounds  from  seventy,  and 
if  the  air  comes  out  full  and  strong  and  the  equalizing 
piston  seats  its  valve  promptly  without  a  leak,  make 
another  reduction  of  fifteen  or  twenty  pounds  more.  With 
this  reduction  the  brake  cylinder  will  have  about  fifty 
pounds  and  train  pipe  thirty.  If  any  train  pipe  check 
valves  leak,  the  fifty  pounds  will  try  to  equalize  with  the 
thirty,  and  make  it  more  than  the  pressure  above  equaliz- 
ing piston,  which  will  raise  and  let  air  blow  out  of  exhaust 
as  fast  as  it  comes  past  the  check  valve. 

To  locate  a  leaky  rotary  or  any  leak  in  brake  valve  that 
lets  off  the  brake,  set  the  brake;  close  the  cut-out  cock 
at  once;  brake  will  stay  set  and  black  hand  will  raise  or 
train  pipe  exhaust  open.  Then  open  cut-out  cock  and 
brake  will  release  through  exhaust  port  of  triple. 

To  locate  a  leaky  graduating  valve,  set  the  brake  with  a 
light  application;  it  will  release  through  exhaust  port  of 
triple  about  as  quick  as  you  can  lap  the  brake  valve. 
Then,  after  recharging  the  auxiliary,  set  with  a  full  appli- 
cation and  brake  should  stay  set. 

When  a  leaky  graduating  valve  lets  off  the  brake  with  a 
light  application,  it  is  because  the  air  from  the  auxiliary 
leaks  past  the  seat  of  valve  7  into  the  brake  cylinder 
until  the  auxiliary  pressure  is  enough  lower  than  train 
pipe  pressure  so  triple  piston  will  move  air  slide  valve  up 
into  exhaust  position,  releasing  air  from  brake  cylinder 
through  the  exhaust  port.  This  it  cannot  do  with  a  full 
application,  as  in  this  case  the  air  pressure  has  equalized 
between  the  auxiliary  and  cylinder,  so  a  leaky  valve  cuts 
no  figure;  air  will  not  pass  through  after  pressures  are 
equal.  A  leaky  piston  ring  in  the  triple  makes  this  matter 
worse,  as  the  train  pipe  and  cylinder  pressures  can 
equalize  and  stick  the  brake.  A  leaky  triple  usually  is  in 
bad  order  in  other  ways. 


DEFECTIVE   DRIVER   BRAKE  105 

57.  Q.     If  the  brake  is  defective  and  leaks  off  through 
piston  packing,  or  any  leaks  in  piping  to  brake  cylinder, 
is  it  any  advantage  to  let  all  the  air  out  of  train  pipe  in 
such  a  case? 

A.  It  seems  to  make  a  leaking  brake  hold  a  little 
longer,  but  it  is  so  short  a  time  that  it  does  not  help  very 
much  to  stop  the  train.  A  gage  put  on  this  brake  cylinder 
will  show  that  it  only  holds  for  a  few  seconds,  and  during 
that  time  with  a  light  pressure.  The  proper  way  is  to  stop 
the  leak. 

58.  Q.     What  makes  the  driver  brake  so  slow  to  take 
hold  if  coupled  to  a  train  when  it  works  all  right  if  engine 
and  tender  are  working  without  a  train? 

A.  Generally  it  is  because  it  leaks  somewhere,  so  the 
air  leaks  out  without  setting  the  brake  when  a  light  reduc- 
tion is  made  for  the  train  brake.  See  about  the  leaks  the 
first  thing.  The  piston  packing  leather  gets  dry  and  hard 
from  being  so  clo.se  to  the  fire  box  and  it  needs  soaking  up 
with  water  and  oil  frequently  in  the  summer  time.  Tal- 
low and  oil  is  good  to  put  in  driver  brake  cylinders,  as  it 
does  not  evaporate  so  quickly  as  oil  or  water  and  keeps  the 
packing  leather  soft  and  pliable.  On  account  of  freezing 
up  no  water  can  be  used  in  the  winter  time,  oil  only.  To 
test  for  leaks,  set  the  four-way  cock  in  plain  triple  for 
straight  air  (if  possible)  ;  this  will  give  you  time  to  go 
around  and  find  the  leaks.  If  the  piston  leather  leaks,  the 
air  will  blow  out  of  hole  in  the  spring  case  or  lower  head 
of  push  down  brake.  Using  the  brake  valve  on  direct  ap- 
plication position  for  service  stops  will  sometimes  kick  the 
driver  brake  off,  after  setting  the  train  brake.  This  is  be- 
cause when  you  use  the  direct  application  port  to  set  the 
brake  you  make  a  heavier  reduction  at  head  end  of  the 
train  pipe  than  at  rear  end.  The  head  end  triples  equalize 
for  this  reduction;  air  from  rear  end  rushes  up  after  you 
close  the  brake  valve  and  releases  head  triples.  This  is 
another  reason  why  the  direct  application  should  never  be 
used  unless  you  want  the  emergency  action  of  every 
brake. 


IO6  STICKING    TENDER    BRAKE 

59.  Q.     Why   does   the  tender   brake   sometimes   stick 
and  refuse  to  let  off  till  auxiliary  is  bled  a  little,  when  all 
the  other  brakes  on  the  train  release  promptly  ? 

A.  Generally  because  not  enough  excess  pressure  is 
carried.  Always  carry  a  sufficient  excess  if  you  want  the 
automatic  brake  to  work  properly.  Some  old  tenders  have 
12  x  33  inch  auxiliary  reservoirs  for  an  8-inch  brake  cyl- 
inder; if,  in  this  case,  the  piston  travel  is  short,  the  brake 
piston  pressure  is  six  or  seven  pounds  higher  than  other 
brakes  equalize  at  and  train  pipe  pressure  must  be  raised 
correspondingly  higher  to  release  tender  brake.  Then  the 
tender  triple  gets  more  sand  and  dirt  in  it  than  any  other 
triple,  which  causes  it  to  wear  and  get  defective.  A  leaky 
triple  piston  packing  ring  will  allow  any  brake  to  stick 
unless  very  high  excess  is  used,  as  it  will  let  air  equalize 
past  the  triple  piston  into  auxiliary  without  moving  piston 
up  to  exhaust  position. 

60.  Q.     If  the  train  pipe  is  charged  up  with  a  high 
pressure  from  main  reservoir  when  brake  is  released  for 
a  second  application  stop,  will  the  brake  set  again  at  once 
with  a  small   reduction  of  train  pipe  pressure? 

A.  It  will  not  set  again  until  the  train  pipe  pressure  is 
reduced  below  the  auxiliary  pressure.  For  example:  If 
the  brake  has  been  set  tight,  the  auxiliary  pressure  will 
be  about  fifty  pounds  for  the  first  application ;  if  you  turn 
ninety  pounds  into  train  pipe  you  must  let  forty  pounds 
out  again,  to  draw  train  pipe  pressure  below  fifty,  before 
the  triple  piston  will  move ;  all  this  time  your  train  is 
getting  nearer  the  stopping  point.  This  is  one  of  the 
reasons  why  you  run  by  when  trying  to  make  a  stop  this 
way;  it  takes  so  long  to  draw  your  train  pipe  pressure 
down  where  it  was  before.  In  case  you  expect  to  apply 
the  brake  at  once  after  releasing  it  wholly  or  partly,  put 
the  brake  valve  on  full  release  for  an  instant,  just  long 
enough  to  charge  up  the  train  pipe  its  whole  length,  and 
then  put  it  on  lap.  This  movement  will  hold  your  train 
pipe  pressure  so  near  the  auxiliary  pressure  that  the  triple 
is  ready  to  act  instantly  with  light  service  application. 


STICKING   BRAKES 

This  is  the  proper  method  of  making  partial  release  if 
you  are  going  to  stop  too  soon  or  expect  that  slippery 
track  will  skid  the  wheels  just  as  the  final  stop  is  made. 

61.  Q.     Why  are  some  of  the  train  brakes  more  likely 
to  stick  on  a  long  train  after  a  light  application  than  after 
a  heavier  one? 

A.  Because  after  a  light  application  the  pressure  has 
been  reduced  so  little  in  the  auxiliaries  that  the  main 
reservoir  does  not  have  enough  more  pressure  to  move  all 
the  triples.  A  light  reduction  on  a  long  train  does  not 
always  move  all  the  triple  pistons  and  their  feed  ports 
remain  open  ready  to  take  train  pipe  air,  which  holds  the 
train  pipe  pressure  down.  With  a  heavy  reduction  the 
triples  all  operate,  no  feed  ports  will  be  open  till  triples 
release  and  the  train  pipe  pressure  will  raise  higher  at  the 
moment  of  releasing  brakes.  This  is  a  trouble  peculiar 
to  long  trains  only;  small  main  reservoirs  and  sticky  triples 
with  leaky  packing  rings  make  it  worse. 

62.  Q.     Is  it  possible  to  let  off  part  of  the  brakes  and 
leave  part  of  them   set? 

A.  Yes.  After  a  full  application  this  can  be  done, 
especially  if  train  pipe  pressure  has  been  reduced  much 
more  than  twenty  pounds.  When  you  go  to  full  release,  if 
the  train  pipe  is  not  at  once  charged  up  above  the  highest 
auxiliary  pressures  by  the  main  reservoir  air,  as  soon  as 
the  train  pipe  pressure  is  a  little  higher  than  the  lowest 
pressure  in  any  auxiliary,  its  triple  will  move  up  into 
exhaust  position,  releasing  that  brake.  Then  this  auxiliary 
will  begin  to  recharge  through  feed  port  and  help  hold 
train  pipe  pressure  down  till  that  auxiliary  and  the  train 
pipe  are  charged  up  high  enough,  when  another  brake  will 
let  off;  and  so  no,  until  all  are  let  off.  The  brake  with 
longest  piston  travel  usually  lets  off  first,  because  it  has 
the  lowest  auxiliary  pressure;  this  operation  takes  place 
after  a  full  application  when  piston  travels  are  unequal. 
When  pumping  off  the  stuck  brakes  you  have  to  raise  the 
pressure  in  all  the  auxiliaries  of  the  released  brakes  as 
well  as  in  the  train  pipe.  When  you  think  the  brakes  are 
releasing  in  this  manner,  lap  the  brake  valve  and  pump 


IO8  BRAKES    CREEPING    ON 

up  the  excess;  when  this  is  turned  back  into  the  train 
pipe  they  will  usually  all  let  go.  Do  not  attempt  to  work 
steam,  you  will  risk  a  break-in-two. 

63.  Why  do   some  of  the  brakes  creep  on  when  the 
train  is  running? 

A.  Because  there  is  a  leak  that  takes  air  out  of  the 
train  pipe;  this  leak  may  be  in  the  train  pipe,  triple  valve 
or  auxiliary  reservoirs.  It  can  also  be  on  account  of  the 
auxiliaries  not  having  all  equalized  after  releasing  the 
brake.  The  auxiliaries  at  the  head  end  of  train  will  charge 
to  a  higher  pressure  on  full  release  than  the  rear  ones ; 
when  the  brake  valve  is  moved  to  running  position  the 
higher  auxiliary  pressure  will  cause  the  head  triples  to 
move  to  service  position.  If  air  is  fed  into  the  train  pipe 
faster  than  it  leaks  out,  the  brakes  will  not  creep  on.  If 
air  sanders  use  so  much  air  that  the  pump  can  not  supply 
air  to  hold  up  main  reservoir  and  train  pipe  pressures  the 
brake  will  set;  this  is  a  main  reservoir  leak  taking  air  out 
of  train  pipe. 

64.  Q.     How  can  these  brakes  be  released  the  quickest 
and  surest  way? 

A.  If  a  main  reservoir  leak  reduces  train  pipe  pressure, 
shut  off  the  escape  of  air  if  possible  and  run  the  pump 
faster  till  train  pipe  pressure  is  raised  so  brakes  will  re- 
lease. If  a  leak  from  train  pipe  sets  the  brake,  see  that 
you  have  excess  pressure  first,  then  turn  it  back  into  train 
pipe  by  moving  the  brake  valve  handle  from  "  running 
position"  to  "full  release"  just  long  enough  so  the,  rush 
of  air  from  main  reservoir  will  charge  up  the  train  pipe, 
and  putting  it  back  to  running  position  before  any  of  the 
auxiliaries  are  charged  any  higher.  This  forces  the  triple 
valves  of  the  sticking  brakes  up  into  release  position,  so 
air  from  brake  cylinder  exhausts  and  does  not  give  time 
to  raise  the  pressure  in  any  reservoir.  Sometimes  this 
must  be  done  a  second  and  third  time  to  release  all  of 
them.  If  brake  valve  is  held  on  full  release  long  enough 
to  charge  a  reservoir  higher  than  the  standard  train  pipe 
pressure,  that  brake  will  be  sure  to  set  as  soon  as  brake 
valve  is  returned  to  running  position.  This  is  the  case 


OVERCHARGING  TRAIN  PIPE  IOQ 

when  the  feed  ports  are  too  large  in  proportion  to  the  aux- 
iliaries that  they  supply. 

65.  Q.     If  governor  is  set  at  seventy  pounds  with  D-8 
valve  or  any  brake  valve  of  that  type,  and  train  pipe  is 
charged   from   main   reservoir   higher   than   that  pressure, 
is  the  brake  apt  to  creep  on? 

A.  Yes;  the  pump  is  stopped  and  will  not  start  again 
till  train  pipe  pressure  is  lowered  to  seventy  pounds.  The 
excess  valve  will  remain  shut  so  no  air  can  pass  into  the 
train  pipe,  and  if  there  are  any  leaks  the  train  pipe  pres- 
sure will  drop.  During  this  time  brake  is  pretty  sure  to 
go  on. 

66.  Q.    How  can  this  be  avoided? 

A.  By  not  allowing  main  reservoir  to  charge  train  pipe 
and  auxiliaries  at  over  seventy  pounds.  When  standing 
at  a  water  tank,  or  any  stop,  with  brakes  set,  the  main 
reservoir  pressure  is  apt  to  run  very  high.  If  all  of  this 
is  turned  into  train  pipe  and  allowed  to  equalize  at  over 
seventy  pounds,  with  brake  valve  carried  in  full  release 
regularly,  there  is  no  way  to  prevent  the  brake  setting  if 
train  pipe  leaks.  In  this  case,  set  it  a  little  and  at  once 
release  it;  this  will  reduce  the  train  pipe  and  auxiliaries 
below  seventy  pounds,  so  pump  will  go  to  work  and  you 
can  hold  brake  off. 

67.  Q.     In  making  a  stop  how  should  you  release  the 
brakes  on  a  freight  train?     On  a  passenger  train? 

A.  On  a  freight  train  not  till  it  has  entirely  stopped, 
or  you  run  the  risk  of  train  breaking  in  two.  The  train 
pipe  pressure  on  a  long  train  is  increased  next  the  engine 
first;  hence  brakes  let  go  there  first;  even  if  it  is  only  a 
few  seconds  sooner.  Part  of  the  shock  is  from  unequal 
piston  travel,  which  gives  unequal  piston  pressure;  brakes 
with  long  piston  travel  let  go  first  after  a  full  application. 
With  a  "  part  air  "  train  the  slack  of  entire  train  runs  up 
against  the  head  cars ;  releasing  brake  while  train  is  mov- 
ing slowly,  is  liable  to  part  the  train;  working  steam  be- 
fore slack  is  all  evened  up  in  train  is  sure  to  break  it  in 
two.  Using  pressure  retainers  on  the  head  end  of  such  a 
train  or  the  Straight  Air  brake  on  engine  will  hold  the 


HO  RELEASING  BRAKES 

slack  all  bunched  till  all  triples  have  released  when  retainer 
handle  can  be  turned  down  or  engine  brake  released. 

With  a  passenger  train,  release  should  be  made  just  a 
few  feet  before  the  train  stops,  so  there  will  be  just  enough 
power  to  stop  the  train  and  avoid  tilting  the  coach  truck 
forward  at  the  instant, the  train  stops.  If  the  brake  beams 
are  hung  from  the  body  of  the  car  the  truck  will  not  tilt 
forward. 

68.  Q.     Why  should  a  brake  on  a  short  passenger  train 
be  let  off  just  before  coming  to  a  full  stop? 

A.  Because,  as  most  all  coaches  have  outside  hung 
brakes,  the  brake  shoes  pull  down  on  the  forward  end  of 
the  truck  and  push  up  on  the  back  part  of  the  truck  and 
thus  tilt  the  truck ;  if  brake  is  not  let  off  until  after  the  train 
stops,  when  the  truck  rights  itself  it  rolls  the  wheels  back 
a  little  and  throws  the  body  of  the  coach  back,  annoying 
the  passengers,  even  if  it  is  not  severe  enough  to  throw 
them  against  the  seats.  This  trouble  is  not  felt  so  plainly 
by  the  engineer  when  he  has  a  good  driver  and  tender 
brake,  as  the  brake  on  the  coach  is  what  jerks  the  coach. 
Then  less  power  is  required  to  stop  a  train  going  very 
slow,  as  at  the  instant  of  stopping,  than  when  running  at 
full  speed;  if  power  enough  is  left  on  to  hold  a  train  at 
full  speed,  it  must  stop  very  forcibly  at  slow  speed.  The 
brakes  should  begin  to  release  about  half  a  rail  length 
from  where  the  train  finally  stops ;  a  little  farther  if  going 
very  fast,  a  little  less  if  a  very  slow  stop  is  being  made. 
Practice  will  teach  you  the  distance. 

There  is  an  exception  to  this  rule  in  the  case  of  a  very 
long  passenger  train,  say  over  twelve  coaches,  especially 
if  it  is  not  vestibuled  and  the  buffer  spring  slack  all  taken 
up  solid  between  the  cars.  Experience  will  teach  you  that 
in  stopping  a  train  of  this  length  less  shock  will  be  given 
the  front  end  of  train  if  brake  is  held  on  moderately  tight 
just  at  the  instant  of  stopping  till  train  stops;  i.  e.,  handle 
a  very  long  passenger  train  about  the  same  as  a  freight 
train  of  the  same  length. 

69.  Q.    How  should  a  "  two  application  stop  "  with  a 
passenger  train  be  made? 


TWO-APPLICATION    STOP  III 

A.  Make  a  full  application  when  running  at  a  high 
speed  so  as  to  have  a  high  brake  power  at  high  speed. 
When  the  speed  is  reduced  to  15  or  18  miles  an  hour,  and 
you  are  stopping  short  of  the  desired  point,  go  to  full  re- 
lease for  an  instant,  just  long  enough  to  start  all  triples  to 
exhaust,  then  begin  the  second  application  at  once  by  a 
moderate  reduction  which  should  set  all  brakes  at  a  mod- 
erate power.  You  can  increase  the  brake  power  with 
another  reduction  so  as  to  stop  at  the  exact  point,  and,  if 
necessary,  leave  the  brake  set  without  having  power 
enough  to  tilt  the  trucks  and  shock  the  passengers.  This 
method  reduces  the  risk  of  sliding  wheels,  as  brake  is  set 
tight  at  high  speed  when  wheels  do  not  slide,  then  let  off 
and  set  with  less  power  at  slow  speed. 

70.  Q.     Describe   the   position   of   the   handles   to   all 
valves  and  cocks  in  the  air  brake  and  signal  equipment, 
whether  open  or  shut. 

A.  All  the  handles,  except  to  angle  cocks,  stand  at 
right  angles  or  crosswise  of  the  pipes  when  they  are  open ; 
parallel  to  pipe  when  "  cut  out " ;  plain  triples  and  pressure 
retainers  follow  the  same  rule,  their  handles  are  horizontal 
or  crosswise  when  "  cut  in  ".  The  crooked  handle  of  angle 
cock  is  parallel  with  pipe  when  cut  in.  This  is  so  the  hose 
will  protect  handle  from  being  struck  by  anything  flying 
under  the  car  and  getting  shut  off,  as  the  old  style  straight 
handled  cock  is  liable  to.  A  small  groove  square  across 
the  end  of  plug  shows  whether  cock  is  open  or  shut,  as  the 
groove  runs  sarrfe  way  with  hole  in  plug. 

71.  Q.    Do  you  understand  that  all  air  cars  in  a  train 
should   be   connected   and   train   pipes   charged   with   air, 
whether  brakes  are  cut  in  or  not?     Why? 

A.  Yes.  All  train  pipes  should  be  coupled  up  and  air 
working  through  them,  so  that  if  the  train  breaks  in  two 
anywhere  in  the  line,  all  brakes  will  be  set  that  are  work- 
ing. Interstate  Commerce  Commission  rules  say  so. 

72.  Q.    What  should  be  done  with  a  car  on  which  the 
train  pipe  is  broken? 

A.     If  it  cannot  be  plugged  at  leak  and  allow  air  to  pass 


112  BROKEN    TRAIN    PIPE 

freely  to  cars  behind  it,  it  must  be  switched  behind  all 
other  air  cars;  have  air  in  hose  that  is  coupled  to  next  car 
in  front;  brakeman  should  look  after  that  car  and  all 
behind  it.  If  you  have  two  ^-mch  air  brake  hose,  the 
signal  hose  can  be  taken  off  signal  line,  brake  hose  put  on, 
and  signal  line  used  for  brake  line  through  that  car  to  get 
air  back  to  other  cars. 

73.  Q.     If  the  pipe  at  one  end  of  the  car  should  come 
loose,  would  you  consider  it  dangerous?     Why? 

A.  Yes.  If  the  pipe  at  end  of  car  gets  loose  so  cock 
will  bounce  up  and  down  and  strike  the  handle  end  of  plug 
against  the  dead  wood  or  any  part  of  car,  it  is  liable  to 
work  shut  gradually.  This  is  caused  by  the  spring  which 
holds  the  plug  in  its  seat,  turning  plug  a  little  each  time 
it  strikes.  If  the  spring  is  wound  one  way,  it  works  open ; 
if  the  other  way,  it  works  shut. 

74.  Q.     i.     After   coupling  to   train   why   should   you 
not  immediately  try  to  apply  the  brakes   for  inspection? 
2.     How   long  should  you  wait? 

A.  Because  you  must  wait  till  a  full  pressure  of  seventy 
pounds  is  stored  in  auxiliaries  so  a  full  application  of 
brakes  can  be  obtained  to  get  the  piston  travel.  The  time 
you  should  wait  depends  on  the  pressure  maintained  in  the 
train  pipe  from  the  moment  of  coupling  on;  if  seventy 
pounds  is  held  steadily,  two  and  one-half  minutes  is  the 
shortest  time  for  some  of  the  older  makes  of  triples.  The 
triple  valves  of  late  design  charge  to  seventy  pounds  in 
about  seventy  seconds.  The  pressures  must  be  equal  in  all 
the  auxiliaries  even  if  it  takes  longer  before  testing.  When 
the  governor  stops  the  pump  with  the  standard  pressures 
shown  on  both  hands  of  the  gage  it  is  usually  long  enough. 

75.  Q.     Should  the  train  brakes  be  inspected?    How? 
When?     Why? 

A.  Yes,  by  applying  them  with  full  service  application 
in  the  same  maner  as  for  a  station  stop  with  a  moving 
train ;  then  examine  each  car  to  see  that  the  piston  travel 
is  the  proper  length  and  that  there  are  no  leaks  that  will 
let  brakes  off;  then  release  them  and  examine  each  car  to 


INSPECTING   BRAKES  113 

see  that  all  release  and  that  there  are  no  leaks  through 
exhaust  port.  They  should  be  inspected  at  all  terminals 
and  tested  whenever  train  breaks  in  two,  or  cars  are  taken 
on  or  set  off,  as  the  wrong  angle  cocks  may  be  closed  or 
left  closed  at  such  points.  This  is  necessary  because  it  is 
not  safe  to  depend  on  a  brake  till  it  is  shown  that  it  will 
set  and  release  properly.  Hand  brake  should  always  be 
let  off  before  testing.  If  pressure  retaining  valves  are 
tested  they  should  be  turned  up  after  the  first  test  is  com- 
pleted, a  reduction  of  ten  pounds  made  in  train  pipe,  and 
the  train  pipe  recharged  to  release  the  triples.  The  re- 
tainers should  then  be  examined  to  see  that  they  are  all 
quiet;  handles  should  then  be  turned  down.  If  they  are 
in  good  order  the  air  held  in  brake  cylinder  will  come  out 
as  soon  as  handle  is  turned  down.  If  no  air  blows  out  the 
retainer  is  useless. 

76.  Q.     Would  you  consider  a  train  safe  to  leave  with 
if  the  brakes  had  been  tested  by  opening  angle  co  ck  at  rear 
of   train?      How   would   this    affect   your    main    reservoir 
pressure? 

A.  No,  sir,  not  unless  some  other  test  has  been  made. 
This  would  not  set  all  the  brakes  unless  the  brake  valve 
was  on  lap.  It  would  draw  down  main  reservoir  pressure 
and  waste  air  without  doing  any  good.  This  test  is  only 
good  to  show  that  air  hose  are  coupled,  angle  cocks  open 
and  train  pipe  charged  from  engine  to  last  car. 

77.  Q.     If  you  release  the  brake  and  apply  it  again 
immediately,  would  you  expect  to  obtain  the  same  power 
you  had  before?     How  long  would  it  take  to  regain  the 
original  pressure? 

A.  No,  sir  \  never.  About  forty  seconds,  if  main  reser- 
voir had  thirty-five  or  forty  pounds  excess  over  auxiliaries; 
sometimes  less  time.  The  feed  ports  in  triple  valves  which 
regulate  the  time  of  charging  are  not  always  the  proper 
size  for  the  reservoirs  they  supply.  A  short  train  and  light 
application  would  reduce  this  time  to  twenty  or  twenty-five 
seconds.  Generally  it  takes  longer  than  the  tests  show  it 
with  everything  in  good  working  order,  for  the  feed  ports 


114  RECHARGING    AUXILIARIES 

are  not  always  clean  and  strainers  free.  The  pressure  at 
which  auxiliary  equalized  after  first  application  is  what  you 
begin  with  on  second  application  after  first  release,  gener- 
ally it  is  fifty  after  first  full  application ;  with  full  release  of 
brake  and  immediate  application  you  get  thirty-five  and  a 
little  more  on  second  full  application;  the  third  time  you 
will  have  less  than  thirty  pounds  piston  pressure. 

78.  Q.     Can  an  auxiliary  reservoir  be  recharged  with- 
out releasing  the  brake? 

A.  No,  not  if  the  triple  valve  is  in  good  order.  The 
ports  are  so  located  in  the  triple  valve  that  the  "  feed  port " 
through  which  auxiliary  is  charged  does  not  open  till  after 
exhaust  port  is  open,  which  releases  the  brake  first,  re- 
charges the  auxiliary  afterward.  By  the  use  of  a  pressure 
retaining  valve,  which  holds  some  of  the  air  in  the  brake 
cylinder,  the  auxiliary  can  be  recharged  without  releasing 
the  brake  entirely. 

79.  Q.     Why  does  it  take  so  long  to  regain  the  original 
pressure  in  the  auxiliaries  after  releasing  brakes? 

A.  Because  the  feed  port  in  the  triple  through  which 
the  air  passes  from  train  pipe  to  auxiliary  is  small.  This 
feed  port  is  shown  at  "  m  "  in  the  plain  triple,  and  at  "  i " 
in  the  quick-action  triple.  It  is  necessary  to  have  this 
port  small  for  two  reasons;  first — when  setting  the  brake, 
the  feed  port  must  be  small  or  when  train  pipe  pressure  is 
reduced  at  brake  valve  for  a  light  service  application,  the 
auxiliary  air  could  flow  around  the  triple  piston  through 
the  feed  port  "  i "  as  fast  as  it  is  taken  out  of  train  pipe ; 
so  triple  piston  would  not  move.  If  the  feed  ports  were 
larger,  when  brakes  are  to  be  released,  it  would  be 
impossible  to  charge  up  a  long  train  pipe  from  the  engine 
and  hold  the  pressure  up  quick  enough  to  release  all  the 
brakes  at  as  nearly  the  same  instant  as  possible,  as  the 
first  few  ports  to  open  would  take  some  of  the  train  pipe 
air  and  hold  the  pressure  down;  if  they  were  large  enough 
a  few  of  them  would  do  this.  The  quick-service  triples 
are  now  arranged  to  help  this  matter  out.  These  feed 
ports  must  be  the  proper  size  for  the  auxiliaries  they  sup- 


LEAKAGE   GROOVES  115 

ply,  so  different  sized  auxiliaries  will  charge  to  the  same 
pressure  in  the  same  time  from  the  same  train  pipe.  The 
auxiliary  reservoir  for  a  lo-inch  coach  brake  holds  about 
3,100  cubic  inches,  that  for  an  8-inch  freight  brake  holds 
about  1,620  inches ;  therefore  a  feed  port  for  a  lo-inch  brake 
reservoir  must  be  the  right  size  to  pass  nearly  twice  as 
much  air  through  in  the  same  given  time  as  for  an  8-inch 
brake.  This  is  the  reason  for  using  only  the  proper  triple 
for  each  reservoir.  Then  the  reservoirs  are  a  certain  size 
for  the  brake  cylinders  they  supply,  so  an  auxiliary  pressure 
of  seventy  pounds  will  equalize  with  brake  cylinder  of  8 
inches  piston  travel  at  fifty  pounds.  This  in  turn  gives  a 
standard  piston  pressure  for  which  to  arrange  the  brake 
leverage  on  each  car  or  engine,  so  as  to  get  the  full  effective 
braking  power.  The  older  style  of  plain  triples,  F-24,  used 
with  8-inch  engine  brakes,  have  feed  ports  the  proper  size 
for  12x33  auxiliaries.  This  gives  a  quicker  recharging 
and  a  prompter  application  with  these  brakes  in  switching 
service.  If  engine  brake  creeps  on  from  this  cause  when 
coupled  to  a  train  they  are  easily  released  as  they  are  close 
to  the  brake  valve  and  main  reservoir.  The  present  style 
of  plain  triples,  G-24,  have  the  proper  sized  feed  ports 
for  the  8-inch  brake. 

80.  Q.  Where  are  leakage  grooves  located?  What  are 
they  for?  Is  it  necessary  to  allow  for  them  when  applying 
the  brake?  How  do  you  do  this? 

A.  Leakage  grooves  are  small  grooves  cut  in  the  inside 
of  brake  cylinders  at  the  top  or  side.  The  later  freight 
brake  cylinders  have  them  at  the  side.  When  the  brake 
piston  is  in  release  position  this  groove  is  uncovered  so 
tfiat  a  small  amount  of  air  passing  into  the  brake  cylinder 
from  a  very  light  application,  or  when  the  brakes  are 
creeping  on,  will  escape  through  the  groove  without  mov- 
ing the  piston.  When  the  triple  valve  is  in  release  posi- 
tion any  air  that  gets  into  the  cylinder  from  leaks  can 
pass  out  through  the  exhaust.  They  also  prevent  the 
brake  holding  when  the  piston  travel  is  taken  up  too 
short.  In  old  equipment  they  are  long  enough  so  that  a 


Il6  PISTON    TRAVEL 

piston  movement  of  three  inches  is  necessary  to  cover  the 
groove,  in  later  equipment  they  are  much  shorter.  It  is 
necessary  to  allow  for  them  at  the  first  reduction  by  mak- 
ing it  strong  enough  so  that  the  brake  piston  will  go  far 
enough  at  the  first  movement  to  cover  the  groove.  Five 
to  seven  pounds  reduction  should  do  this ;  a  short  train 
does  not  take  as  heavy  a  reduction  as  a  long  one.  The 
leakage  groove  must  be  covered  at  the  first  reduction  or 
the  air  passing  into  the  cylinder  will  be  wasted,  a  number 
of  small  reductions  will  waste  all  the  air  so  train  cannot 
be  stopped.  This  is  a  common  fault  in  operating  the 
brake.  If  the  hand  brake  is  set  on  a  coach  or  the  piston 
travel  shortened  to  less  than  three  inches  that  brake  will 
not  hold. 

81.  Q.     Does    the    difference    in    travel    of   pistons    in 
brake  cylinders  increase  or  decrease  your  braking  power? 
Why? 

A.  Long  piston  travel  decreases  the  braking  power 
because  it  gives  less  air  pressure  on  piston,  short  piston 
travel  gives  higher  piston  pressure.  With  8-inch  piston 
travel,  seventy  pounds  auxiliary  pressure  gives  fifty  pounds 
on  piston  per  square  inch.  An  inch  difference  in  the  travel 
make  close  to  two  pounds  in  pressure,  thus  seven  inches 
would  give  nearly  fifty-two  pounds,  nine  inches  a  little 
over  forty-eight  pounds.  The  piston  travel  can  be  correct 
with  a  heavy  car  and  high  leverage,  and  the  shoes  will  not 
clear  the  wheel  much  when  released.  If  levers  and  brake 
beams  spring  much  with  8-inch  travel,  the  shoes  will  not 
have  much  slack  when  let  off.  Brake  levers  may  catch  on 
something  so  piston  travel  is  correct  and  shoes  not  touch 
the  wheels.  With  the  straight  air  brake  or  the  distributing 
valve  the  piston  travel  does  not  affect  the  pressure  on  the 
brake  piston,  as  these  valves  do  not  take  air  from  an  aux- 
iliary as  the  triple  valve  does. 

82.  Q.     How  do  you  cut  out  the  brake  on  engine  and 
tender  without  interfering  with  the  train  brake? 

A.  By  turning  the  four-way  cock  in  top  of  plain  triple 
so  the  handle  is  at  an  angle  of  forty-five  degres ;  this  will 


CUTTING  OUT  BRAKES  117 

lap  all  ports  and  allow  no  air  to  pass  from  train  pipe  or 
auxiliary  to  brake  cylinder;  see  that  brake  is  entirely 
released  first,  and  open  bleeder  in  auxiliary.  With  the 
latest  type  of  engine  triple  the  cut  out  cock  is  in  the  cross 
over  pipe,  so  closing  the  cock  cuts  out  the  triple.  Open 
bleeder  in  auxiliary  so  the  brake  cannot  creep  on  from  a 
leak  in  the  triple. 

83.  Q.     What  is  the  difference  between  cutting  the  air 
out  from  a  car  and  cutting  it  out  from  a  brake  ? 

A.  Shutting  the  angle  cock  at  the  end  next  engine  cuts 
out  that  car  and  all  behind  it;  shutting  the  cock  between 
train  pipe  and  triple  cuts  out  that  brake  only  and  allows 
all  the  rest  to  operate. 

84.  Q.     If  one  brake  beam   under  a   car   was   broken 
how  would  it  affect  that  brake?     How  would  you  cut  out 
the  brake  on  that  car  and  allow  air  to  pass  to  other  cars? 

A.  If  one  brake  beam  or  rod  is  broken,  the  brake  on 
that  car  is  useless  and  it  must  be  cut  out  by  shutting  the 
cock  in  the  crossover  from  train  pipe  to  triple,  or  by  turn- 
ing the  four-way  cock  in  plain  triple.  This  will  allow  air 
to  pass  through  train  pipe  to  other  cars  without  operating 
disabled  brake.  Be  sure  the  brake  with  plain  triple  on 
either  engine,  tender  or  coach  is  released  before  it  is  cut 
out,  as  no  air  can  get  out  of  brake  cylinder  after  cock  is 
turned.  The  plain  triple  used  on  freight  equipment  before 
the  quick  action  triple  was  perfected,  which  is  still  in 
service  on  a  great  many  freight  cars,  bleeds  the  brake 
cylinder  when  the  handle  of  plug  cock  in  triple  is  turned 
to  the  cut  out  position  but  does  not  bleed  the  auxiliaries, 
so  the  brake  is  likely  to  set  when  handle  of  cock  is  turned 
to  automatic  again.  There  is  no  bleeder  in  the  cast  iron 
auxiliary  for  this  triple  and  the  air  escapes  from  brake 
cylinder  through  a  bleed  hole  in  the  plug  of  cut  out  cock. 
This  is  shown  in  question  100.  If  this  hole  gets  stopped 
up,  cut  out  the  car  from  the  others,  open  the  stop  cock  at 
hose,  turn  the  cock  in  triple  for  straight  air  and  air  will 
escape  from  brake  cylinder  through  train  pipe,  after  which 
the  cock  in  triple  can  be  set  for  cut  out  position.  All 


Il8  BRAKING  ON    STEEP   GRADES 

quick  action  brakes  can  be  bled  by  opening  the  bleeder  in 
auxiliary  reservoir  and  allowing  all  air  to  escape,  as  the 
cut  out  cock  does  not  close  the '  communication  between 
brake  cylinder  and  the  bleed  cock  in  auxiliary. 

85.  Q.  -In  going  down  a  long,  steep  grade  how  would 
you  handle  the  brake  to  control  the  train?  Why  is  it 
necessary  to  recharge  the  auxiliaries  on  a  hill?  How  is 
this  done? 

A.  Air  braked  trains  on  a  long,  steep  grade  must  be 
taken  down  at  a  moderate  speed  in  order  to  control  the 
train;  much  less  brake  power  will  hold  it  at  a  slow  speed 
than  a  fast  one.  If  the  train  once  gets  the  start  of  you  it 
may  not  be  held  at  all.  Run  slow  enough  so  you  will  not 
need  all  the  brake  power  to  steady  the  train,  or  you  will 
not  be  able  to  stop  when  necessary. 

Leaks  in  train  pipe,  auxiliary,  or  brake  cylinder  pres- 
sures make  it  necessary  to  recharge;  very  few  if  any 
trains  are  absolutely  air  tight.  If  train  pipe  leaks,  the 
brake  will  set  at  full  power,  which  should  stop  the  train; 
this  will  call  for  a  release  and  recharging  to  standard  pres- 
sure. Auxiliary  or  brake  cylinder  leaks  ,will  reduce  the 
braking  power  so  train  will  run  away;  to  avoid  this  dis- 
aster it  is  necessary  to  recharge  the  auxiliaries  frequently; 
you  can  then  hold  the  auxiliary  pressure  up  close  to  the 
standard  amount  all  the  way  down  the  hill  and  have  plenty 
of  brake  power.  As  triple  valves  release  a  brake  and  re- 
charge the  auxiliary  afterward,  to  hold  the  brake  set  while 
auxiliaries  are  recharging,  pressure  retaining  valves  are 
used,  which  hold  some  of  the  air  in  the  cylinder  after- triple 
has  gone  to  release  position.  Before  starting  down  the 
grade  turn  up  the  handles  of  retainers,  use  as  many  as 
possible  and  not  have  them  stop  the  train  at  any  of  the 
let-ups  in  the  grade.  The  more  retainers  used  the  less  hot 
wheels,  as  the  holding  power  is  on  a  greater  number  of 
cars;  if  the  full  brake  power  is  used  on  any  cars  all  the 
way  down  a  long  hill  the  wheels  are  liable  to  get  so  hot  as 
to  damage  them.  Make  a  moderate  application  at  first; 
when  the  train  slows  down,  release  and  leave  brake  valve 


PART    AIR    TRAINS  IIQ 

in  full  release  position  to  recharge  as  quickly  as  possible, 
which  should  not  take  over  forty-five  seconds.  On  the 
next  application,  a  light  reduction  will  usually  steady  the 
train,  as  with  retainers  used  the  pistons  are  over  the  leak- 
age grooves  and  considerable  pressure  held  in  the  cylinders. 
Light  reductions  give  more  power  to  brakes  with  retainers 
working  than  heavy  reductions  without  the  retainers;  this 
saves  both  train  pipe  and  auxiliary  air.  Pick  out  places 
where  sharp  curves  or  let-ups  in  the  grade  slow  up  the 
train  to  recharge  auxiliaries.  Air  braking  on  a  long  hill 
should  be  learned  on  that  particular  hill — no  exact  rule  can 
be  set  down;  the  instructions  here  given  are  general.  To 
test  the  brake  power  developed  on  various  cars,  feel  of  the 
wheels  at  the  bottom  of  the  hill  when  possible ;  cold  wheels 
on  some  cars  and  hot  wheels  on  others  show  unequal  brak- 
ing power.  Use  the  independent  engine  brake  while  re- 
charging, this  will  help  hold  the  train. 

86.  Q.     What  is  the  difference  between  handling  a  long 
train  having  part  air  in  front  and  one  entirely  of  air? 

A.  A  great  difference.  It  requires  more  skill  and 
practice  to  make  a  good  stop  with  a  part  air  train  than 
with  a  full  air  train.  With  part  air  you  must  be  careful  to 
"  bunch  the  train  "  so  slack  will  run  up  easily  against  the 
air  brake  cars  before  setting  the  brake  very  tight;  this 
takes  some  seconds.  If  you  make  a  second  reduction 
before  the  rear  end  feels  the  effects  of  the  first  one,  the  two 
light  applications  make  one  heavy  one,  as  far  as  the  shock 
to  the  rear  cars  is  concerned.  When  backing  up,  extra 
care  must  be  taken,  or  train  will  break  in  two  and  merchan- 
dise be  damaged  in  cars.  With  a  full  air  train  the  first 
reduction  of  train  pipe  pressure  takes  so  much  longer  to 
start  all  the  triples  to  work  that  you  must  wait  about  as 
much  longer  after  the  train  pipe  exhaust  stops  flowing 
before  making  a  second  reduction.  The  brakes  are  longer 
in  releasing,  and  this  requires  more  time  after  releasing 
before  the  train  runs  free. 

87.  If  you  had  a  freight  train  with  "part  air"  cars 
in    operation    and    you    used    the    emergency    application, 


120  DOUBLE    HEADING 

would  it  make  any  difference  whether  the  slack  was  out  or 
not?  In  case  there  was  a  shock,  on  what  part  of  the  train 
would  it  fall? 

A.  Using  the  emergency  brake  with  part  air  train 
always  sets  the  head  end  hard  and  solid;  if  slack  is  all  run 
up  against  the  engine  the  shock  is  not  as  great.  In  any 
case  the  rear  end  gets  all  the  damage;  the  weakest  cars 
and  draft  gear  behind  air  cars  suffer.  Empty  flat  cars  next 
the  air  are  likely  to  be  wrecked. 

88.  Q.  Which  engineer  should  handle  the  brakes  in 
double-heading,  and  what  should  the  other  engineer  do? 

A.  The  leading  engineer  should  handle*  all  the  brakes 
when  double-heading,  as  he  is  the  only  man  who  can  see 
clearly  all  the  signals  and  the  condition  of  the  track  ahead, 
so  as  to  act  promptly  to  stop  the  train  when  necessary. 
The  following  engineer  should  shut  the  cut  out  cock  under 
his  brake  valve,  which  should  be  in  running  position 
with  the  1892  valve,  on  lap  with  the  H-5  valve,  keep  the 
pump  running  and  a  full  supply  of  air.  If  there  is  no 
cut  out  cock,  place  brake  valve  on  lap  so  no  air  can  get  into 
the  train  pipe  from  his  main  reservoir  and  plug  up  train 
pipe  exhaust  elbow,  so  that  when  head  engineer  releases 
brakes  the  train  pipe  air  will  not  escape  through  second 
brake  valve.  If  cut  out  cock  works  open  or  is  left  open 
so  main  reservoir  air  feeds  into  train  pipe ;  when  the 
leading  engineer  makes  a  service  reduction  the  air  from 
the  following  engine  will  hold  the  equalizing  piston  of 
head  engine  up  so  that  train  pipe  exhaust  will  blow  strong 
and  continuously.  If  head  man  is  sure  that  second  engine 
is  feeding  into  the  train  pipe  when  brakes  are  to  be  set, 
he  should  go  to  emergency  at  once,  whistle  for  brakes,  get 
stopped  or  have  second  cut  out  cock  closed.  The  emer- 
gency port  of  first  brake  valve  will  take  air  out  of  train 
pipe  faster  than  the  second  pump  and  reservoir  can  supply 
it,  especially  if  second  valve  is  on  running  position. 

When  testing  the  train  brakes  from  a  double-header  be 
sure  that  main  reservoir  air  of  following  engines  is  cut  out 
from  train  pipe  and  that  the  test  is  properly  made  from 
leading  engine. 


BURSTED    HOSE  121 

If  the  rules  allow  it  and  a  definite  arrangement  is  made 
between  the  engineers,  the  second  man  can  assist  in  releas- 
ing stuck  brakes  or  in  charging  auxiliaries  by  opening  his 
cut  out  cock  when  signalled  to  do  so  with  brake  valve  in 
full  release.  As  soon  as  train  is  moving  cut-out  cock 
should  be  shut  so  the  leading  engineer  can  stop  the  train 
at  once  if  necessary. 

The  rule  to  carry  brake  valve  on  running  position  with 
cut-out  cock  shut  varies  on  different  railroads.  One  prom- 
inent system  requires  that  the  brake  valve  be  carried  on 
emergency  position  so  that  in  case  of  necessity  brake 
will  go  on  at  once  if  cut-out  cock  is  opened.  Rules  of 
your  own  road  apply  in  this  case  to  position  of  valve. 

89.  Q.     What   would   you    do   if  an   air   hose   burst? 
How  would  you  know  it?     Should  you  have  extra  hose? 
Of  what  kinds? 

A.  Put  brake  valve  on  lap;  whistle  out  a  flag.  If  in 
a  dangerous  place  to  wait,  or  when  a  train  is  close  behind, 
shut  the  first  cock  ahead  of  bursted  hose ;  let  off  brakes  on 
head  end  from  engine;  bleed  the  cars  behind  bursted  hose; 
get  to  a  safe  place  and  replace  the  bursted  hose  with  a  new 
one.  If  with  bad  grades  or  all  air  train,  put  in  a  new  hose 
any  way,  if  possible.  It  would  be  known  at  once  because 
brake  would  set;  black  hand  would  drop  way  down;  main 
reservoir  pressure  would  also  run  down  quickly.  Put 
brake  valve  on  lap  to  save  your  main  reservoir  air.  To 
locate  the  bursted  hose  put  brake  valve  on  running  position 
just  so  you  will  keep  a  little  pressure  in  the  hose  and 
trainmen  can  hear  the  air  blowing  out  of  bursted  hose  and 
find  it. 

Extra  hose  should  be  carried  on  engine,  one  of  each 
kind  used.  Trainmen  should  have  a  i-inch,  a  1%-inch, 
a  signal  hose  and  one  double  end  or  splice  coupling  to  use 
in  case  drawheads  or  coupling  of  cars  are  so  long  the 
regular  hose  and  couplings  will  not  meet  each  other. 

90.  Q.  *  What   course   would   you   take   should   your 
train  break  in  two  and  set  the  brakes? 

A.     Put  brake  valve  on  lap,  shut  off  steam,  whistle  out 


122  PRESSURE  RETAINING  VALVE 

a  flag,  shut  the  open  angle  cock  on  rear  end  of  last  car 
connected  to  engine,  let  off  brakes  on  head  section  from 
the  engine.  When  they  are  released  and  you  get  a  signal 
to  do  so,  back  up  to  rear  section;  after  coupling  up  to  it, 
if  brakes  cannot  be  let  off  from  engine,  bleed  a  few  of  the 
sticking  ones  at  back  end  of  train  until  train  can  be  started. 
Be  very  careful  to  shut  the  bleeder  as  soon  as  air  begins 
to  escape  from  triple  exhaust  port  or  you  will  set  some  of 
the  others,  and  that  will  hold  the  train  longer  than  neces- 
sary. All  air  bled  out  is  wasted;  it  is  done  only  to  save 
time,  which  is  valuable  in  a  case  of  breaking  in  two.  If 
you  break  in  two  or  burst  a  hose  on  a  bad  grade,  shut  both 
angle  cocks  next  the  opening  in  hose,  this  will  save  any 
air  that  leaks  past  the  triples  into  the  train  pipe  and  hold 
leaky  brakes  set  till  you  are  ready  to  release  them  to  move 
the  train. 

91.  Q.  Do  you  know  what  the  "  pressure  retaining 
valve"  does?  And  how?  If  the  pipe  leading  to  this  valve 
should  break  off  would  you  plug  it?  If  you  did,  how  would 
it  affect  the  brake  ?  • 

A.  The  pressure  retaining  valve  holds  some  of  the 
compressed  air  in  the  brake  cylinder  after  the  triple  valve 
has  moved  to  exhaust  position.  It  is  attached  to  exhaust 
port  of  triple  valve  by  a  piece  of  pipe  and  placed  where  it 
can  be  conveniently  reached  when  train  is  in  motion. 
When  set  to  operate,  its  handle  is  turned  up  to  a  horizontal 
position,  which  closes  the  direct  opening,  so  the  air  goes 
out  slowly  under  a  weighted  valve;  and  then  passes  out  of 
the  case  of  valve  through  a  small  opening  so  air  escapes 
slowly.  When  pressure  falls  to  fifteen  pounds  per  square 
inch  in  brake  cylinder,  this  valve  shuts  off  the  escape  alto- 
gether and  holds  the  air  in  there,  keeping  the  brake  set 
at  fifteen  pounds;  this  allows  the  auxiliary  reservoir  to  be 
recharged  to  full  pressure  again.  It  is  use  d  on  long,  steep 
grades.  If  the  pipe  leading  from  the  triple  valve  exhaust 
to  the  retainer  was  broken  off  that  retainer  would  be  use- 
less. The  pipe  should  never  be  plugged,  as  that  brake 
would  not  let  off  at  all ;  there  would  be  no  way  for  the  air 
to  get  out  of  the  brake  cylinder. 


OPERATING  RETAINING  VALVES  123 

92.  Q.    When  air  blows  out  steadily  from  the  pressure 
retaining  valve,  should  it  be  closed  or  left  open? 

A.  Left  open  by  all  means.  The  air  that  blows  out 
there  comes  from  a  leak  in  the  triple  valve;  shutting  the 
pressure  retainer  only  stops  air  coming  out  there  and  sets 
the  brake,  or  if  leak  is  a  small  one,  makes  it  go  out  through 
the  leakage  groove  in  the  brake  cylinder.  If  pressure  re- 
tainer is  turned  up,  even  if  the  brake  does  not  set  right 
off,  it  will  stay  set  when  engineer  sets  it  and  tries  to  let  it 
off.  Never  turn  up  retainers  unless  you  want  to  hold  the 
brake  set  the  next  time  engineer  releases  it.  If  the  pres- 
sure retainer  is  broken  off  or  the  pipe  leading  to  it  from 
triple  is  broken  or  leaking  badly,  it  does  not  affect  the 
operation  of  the  brake  in  any  way,  except  that  the  retainer 
cannot  be  used  on  that  car.  If  retainer  is  broken  off  and 
pipe  plugged  the  brake  cannot  be  released  at  all  from  the 
engine,  as  there  is  no  way  for  air  to  escape  from  triple 
valve  exhaust.  If  there  is  a  leak  in  pipe  from  triple  valve 
to  retainer,  the  retainer  is  of  no  use,  as  air  will  escape 
from  the  pipe  at  leak  when  retainer  is  set  to  work.  Some- 
times the  pipe  to  pressure  retainer  gets  stopped  up  so  air 
cannot  get  through  it,  in  which  case  the  brake  will  set 
once  and  not  release  till  bled  off.  It  is  not  unusual  to  find 
nests  of  insects  in  the  pipe  right  at  retainer.  Pressure 
retainers  are  put  on  all  freight  cars  used  in  interchange 
service.  Very  few  coaches  have  them,  only  those  running 
on  mountain  roads.  Sleepers  and  official  cars  usually  have 
retainers.  They  are  used  on  level  roads  extensively  to 
hold  the  slack  bunched  in  a  long  train;  in  this  case  they 
are  usually  applied  to  the  driver  brake  triple  valve  and 
located  in  the  cab  in  easy  reach  of  the  engineer.  They 
are  valuable  aids  in  making  smooth  stops  with  freight 
trains  at  water  plugs. 

93.  Q.     How  does  the  air  signal  operate?     If  the  air 
signal  on  the  engine  whistled  each  time  you  released  the 
brakes,  what  would  be  the  trouble?     If  the  whistle  blows 
frequently  when   not   in  use,  what  is  the  matter?     If  it 
blows  one  long  blast?     If  the  whistle  is  weak  on  engine 


124  AIR   SIGNAL 

will  it  usually  help  it  to  blow  out  the  signal  hose  on  the 
rear  of  tender? 

A.  The  air  signal  valve  on  the  engine  is  operated  by  a 
reduction  of  pressure  made  in  the  signal  line.  This  signal 
line  is  supplied  with  air  from  the  main  reservoir  which 
passes  through  a  reducing  valve  set  at  a  much  lower  pres- 
sure than  the  standard  braking  pressure,  so  the  operation 
of  the  brake  will  not  interfere  with  the  operation  of  the 
signal.  The  opening  through  the  reducing  valve  is  choked 
down  to  restrict  the  flow  of  air  into  the  signal  pipe  and 
allow  a  reduction  to  be  made  in  its  pressure.  This  reduc- 
tion must  be  a  sudden  one,  like  an  emergency  reduction 
for  the  triple  valve,  or  the  reducing  valve  will  feed  air  into 
the  signal  pipe  as  fast  as  it  is  taken  out  at  the  car  dis- 
charge valve.  When  the  pressure  is  reduced  in  the  signal 
line  at  the  car  discharge  valve  and  this  reduction  extends 
to  the  signal  valve,  it  affects  the  pressure  in  chamber  A 
above  the  diaphram  12  first,  so  that  the  pressure  in  B 
under  the  diaphram  lifts  it  up,  also  raising  the  discharge 
valve  10  off  the  seat  at  7,  which  allows  the  air  to  pass  to 
whistle. 

If  the  diaphram  gets  bagged  down,  the  pressure  in  B 
will  raise  the  baggy  part  of  the  rubber  and  valve  will  not 
raise  off  the  seat. 

The  stem  of  valve  10  has  the  sides  flattened  except  for 
a  short  distance  at  the  top,  where  it  enters  bushing  9, 
when  this  stem  rises  the  flattened  part  comes  above  bush- 
ing 9,  and  air  from  B  also  goes  to  the  whistle,  this  reduces 
the  pressure  in  B.  When  the  car  discharge  valve  is  closed 
and  the  signal  line  pressure  is  increased  by  the  reducing 
valve,  as  the  stem  of  10  makes  a  moderately  close  fit  in  the 
top  of  bushing  9,  air  passes  into  B  slowly  while  recharging. 
Chamber  A  is  therefore  charged  up  first  so  diaphram  is 
sure  to  set  valve  10  promptly. 

If  the  fit  of  the  stem  at  the  top  of  the  bushing  is  too 
loose  the  valve  is  liable  to  rise  on  its  seat  so  the  signal 
will  "  repeat "  and  give  more  than  one  blast  for  each  pull 
of  the  car  discharge  valve. 


Signal  Valve, 


To  Main 

To  Main       Reservoir 


Pressure  Reducing  Valve. 


Improved  Reducing  \ 
Valve, 


126  AIR    SIGNAL    DEFECTS 

This  fit  must  be  exact  or  the  signal  valve  will  not 
always  respond  on  both  long  and  short  trains  to  the  pro- 
per reductions. 

If  an  air  signal  whistles  each  time  brake  is  released 
with  standard  braking  pressure,  it  is  a,  sign  the  reducing 
valve  is  dirty  and  stuck  open,  so  air  goes  back  into  main 
reservoir  from  signal  line  each  time  main  reservoir  pres- 
sure is  reduced  in  recharging  train.  In  this  case  signal 
line  has  main  reservoir  pressure.  Clean  the  reducing 
valve  before  the  air  signal  hose  bursts.  The  whistle  will 
give  a  shrill  sound  if  pressure  is  too  high.  If  the  spring 
in  the  old  style  reducing  valve  over  diaphram  is  too  stiff  it 
will  do  this.  The  improved  reducing  valve  is  regulated  for 
the  proper  pressure  in  the  same  manner  as  the  feed  valve 
on  F-6  brake  valve.  The  reducing  valves  are  set  at  about 
forty-five  now;  the  old  valves  were  set  at  twenty-five 
pounds.  This  is  so  as  to  carry  a  lower  pressure  in  signal 
line  than  is  used  to  operate  the  brake.  To  test  the  pres- 
sure at  which  reducing  valve  operates,  shut  off  the  pump, 
reduce  the  main  reservoir  about  five  pounds  at  a  time 
through  brake  valve  till  the  signal  whistle  blows ;  this 
shows  that  the  reducing  valve  is  held  open  by  the  spring 
so  air  can  pass  from  signal  pipe  into  main  reservoir.  If 
the  signal  whistle  blows  frequently  when  not  in  use, 
there  is  a  leak  somewhere  which  the  jar  of  the  engine 
may  open  for  an  instant,  or  the  reducing  valve  may  be  out 
of  order.  If  it  sticks  a  little  in  its  seat,  as  in  cold 
weather,  a  very  small  leak  will  cause  the  whistle  to  give 
a  strong  blast — or  a  jar  may  unseat  signal  valve.  When 
it  blows  one  long  whistle  some  of  the  valves  on  engine 
are  stuck,  or  the  car  discharge  valve  is  opened  a  second 
and  third  time  before  the  whistle  stops  blowing  the  first 
blast;  the  pressure  in  signal  line  must  equalize  each 
time  between  the  blasts  to  make  it  work  accurately.  If 
the  stem  10  makes  too  close  a  fit  in  bushing  9  the  whistle 
will  give  only  one  blast  for  two  or  more  reductions  of  sig- 
nal line  pressure,  or  a  very  small  leak  in  the  signal  litif 
will  cause  signal  valve  to  operate  at  intervals,  when  a 


AIR     SIGNAL    OPERATIONS  127 

proper  fit  would  allow  it  to  work  properly.  If  the 
whistle  bell  works  loose  so  it  does  not  make  a  clear 
sound,  or  is  located  near  partly  opened  windows  so  a 
strong  draft  of  air  blows  across  it,  when  train  is  run- 
ning fast,  fhe  sound  will  be  very  weak.  Blowing  out 
the  signal  hose  at  rear  of  tender  gives  all  the  valves  a 
chance  to  make  a  full  opening  and  clean  out  the  dirt. 
To  test  the  signal  line  for  leaks,  shut  the  cut  out  cock  at 
the  reducing  valve ;  if  the  signal  line  leaks,  the  whistle  will 
blow  as  soon  as  the  leak  reduces  the  pressure.  On  a 
double  header  both  whistles  should  sound  for  the  same 
reduction  of  signal  line  pressure.  If  they  do  not,  close  the 
cock  in  the  reducing  valve  on  the  following  engine  so  only 
one  reducing  valve  will  be  feeding  into  the  train  signal 
line  and  thus  allow  the  car  discharge  valve  to  do  its  work 
properly.  With  both  reducing  valves  cut  in  the  signal 
valve  will  not  always  operate  on  the  leading  engine  when 
the  train  pipe  reduction  is  made  from  the  rear  cars  of  a 
long  train. 

With  the  E.  T.  locomotive  brake  the  same  reducing 
valve  is  used  for  the  independent  brake  valve  and  the  air 
signal  system.  There  is  a  non-return  check  valve  in  the 
signal  pipe  so  the  air  can  not  get  back  from  the  signal  pipe 
when  the  independent  valve  takes  air  to  apply  the  brake 
as  it  would  sound  the  whistle. 


FOR  TRAINMEN. 

94.  Q.     When   coupling   the   engine   to   an   air   brake 
train,    equipped    with    quick    action    triples    and    already 
charged  with  air,  which  angle  cock  should  be  opened  first? 

A.  The  one  on  engine  always,  so  as  to  fill  the  hose 
from  engine.  If  cock  on  car  is  opened  first,  the  train  brake 
is  liable  to  set  with  emergency  action.  Get  in  the  habit  of 
opening  the  cock  on  engine  first,  whether  train  is  charged 
or  empty. 

95.  Q.     When    coupling   an   empty   car   to   other   cars 
already  charged  and  working,  how  should  the  angle  cocks 
be  opened? 

A.  Open  the  one  on  empty  cars  first,  so  the  empty 
train  pipe  and  empty  hose,  will  be  connected.  Then  open 
the  angle  cock  on  the  charged  car  slowly  so  the  pressure 
in  train  pipe  will  not  be  reduced  any  faster  than  the  engine 
can  supply  it.  This  will  prevent  the  brakes  setting  on 
head  end  of  train,  which  they  will  do  with  emergency 
action  if  angle  cock  is  opened  suddenly.  A  little  practice 
will  teach  you  the  advantage  of  this.  This  applies  to  coup- 
ling up  the  air  on  a  train  that  has  been  separated  to  open 
public  crossings.  When  coupling  to  cars  on  a  side  track 
that  are  going  with  your  train,  make  the  air  brake  con- 
nections also,  so  the  auxiliaries  will  be  charging  ready  for 
operating  the  brake  while  you  are  getting  out  on  the  main 
track,  this  will  save  time  in  testing  the  brakes,  as  they 
will  be  ready  when  train  is  all  coupled  up.  When  air 
braked  cars  are  to  be  set  on  a  coming  train,  charge  these 
cars  with  air  from  the  engine  used  to  place  them  on  the 
train,  it  saves  delay. 

96.  Q.     If  an  angle  cock  at  head  of  end  train  is  only 
partly  opened  or  there  is  an  obstruction  in  the  train  pipe, 
how  will  it  affect  the  operation  of  the  brake? 

A.  The  brake  can  be  set  with  service  application,  but 
it  releases  very  slowly  as  the  air  does  not  get  back  fast 
enough  to  move  all  the  triple  valves  to  release  promptly, 


130  MAKING    UP    TRAINS- 

and  any  triples  with  defective  packing  rings  back  of  the 
obstruction  will  be  sure  to  stick.  With  angle  cock  on  ten- 
der partly  open,  you  cannot  always  get  the  emergency 
action  of  the  brake.  When  passing  over  the  top  of  the 
train,  angle  cocks  can  be  inspected,  as  they  are  generally 
for  enough  outside  the  end  of  car  so  the  handles  are  visible 
from  top  of  car.  When  cocks  are  wide  open  the  handles 
are  exactly  over  the  hose.  The  old  style  plug  shut-off 
cocks  come  in  the  straight  pipe  just  under  the  end  of  car 
and  cannot  be  seen  when  passing  over  the  cars. 

97.  Q.     Can  an  air  brake  train  be  made  up  so  it  will 
be  impossible  to   get  the   emergency  action  of  the  brake 
from  the  engineer's  brake  valve? 

A.  If  there  are  four  cars  with  the  brakes  cut  out  at 
cross  over  near  triples,  or  four  cars  with  train  pipe  only, 
or  with  plain  triples,  next  to  the  engine,  the  reduction  of 
air  pressure  in  train  pipe  will  be  so  gradual  on  the  fifth 
car  that  you  cannot  get  the  emergency  application  of  the 
quick  action  triples.  It  takes  a  sudden  reduction  at  the 
first  quick  action  triple  to  get  the  emergency.  Switch  the 
plain  triples  among  the  quick  actions;  you  may  need  them 
to  make  a  sudden  stop  in  an  emergency. 

NOTE — These  questions  refer  to  quick  action  equipment. 
With  the  plain  triple  valves,  such  as  are  still  used  on 
many  roads  on  their  passenger  equipment,  it  does  not  make 
very  much  difference  which  angle  cock  is  opened  first. 
It  is,  however,  better  to  fill  the  hose  in  all  cases  from  the 
engine  or  head  end  of  train. 

98.  Q.     Why    should    train    brakes    be    tested    before 
leaving  a  terminal  or  any  point  where  the  make-up  of  the 
train  has  been  changed?     How  should  this  test  be  made? 

A.  So  you  will  know  before  starting  out  that  the  brakes 
will  work  when  necessary.  After  coupling  the  engine  on 
the  train  the  pressure  should  be  equalized  in  all  the  aux- 
iliaries, so  all  the  brakes  will  set  at  the  same  reduction  of 
train  pipe  pressure.  The  pressure  should  be  seventy 
pounds  in  the  auxiliaries  in  order  to  get  a  full  application 
of  the  brakes  to  test  the  piston  travel.  While  the  engine 


INSPECTING   BRAKES  131 

is  charging  the  train  to  standard  pressure,  which  will  take 
some  time  on  a  long  train,  a  careful  inspection  should  be 
made  for  leaks,  and  to  see  that  all  train  pipe  cocks,  cross- 
over cocks  and  pressure  retainer  handles,  are  in  the  proper 
position  to  operate  all  the  brakes.  When  standard  pres- 
sure is  reached  the  brakes  should  be  applied  from  the  en- 
gine that  is  to  handle  them  with  a  full  service  application 
made  in  the  same  manner  as  when  making  a  station  stop 
of  the  moving  train.  The  train  men  or  inspector -will  then 
examine  each  brake  to  see  that  it  is  set  with  not  less  than 
five  nor  more  than  nine  inches  piston  travel.  When  all 
brakes  are  inspected  if  they  are  set  properly  he  will  give  a 
signal  to  the  engineer  to  release  brakes  and  examine  each 
brake  to  see  that  they  have  released  properly.  If  any 
brakes  require  adjustment  of  piston  travel  it  must  then  be 
done.  Be  sure  to  close  the  cut-out  cock  in  the  cross-over 
while  doing  any  work  on  the  levers  or  shoes,  so  the  brake 
will  not  set  and  injure  the  workman,  opening  it  when  ad- 
justment is  made.  If  pressure  retainers  are  to  be  used, 
they  should  be  tested  after  the  piston  travel  is  tested,  by 
applying  the  brakes  with  a  ten  pound  reduction,  with 
retainer  handles  turned  up.  As  soon  as  the  retainers  are 
quiet,  go  along  and  turn  down  the  handles,  the  air  should 
blow  out  from  each  of  them,  which  shows  that  they  hold 
the  pressure  in  cylinders.  Long  freight  trains  can  be 
tested  by  two  inspectors,  one  at  each  end  working  towards 
the  middle  of  the  train  till  they  meet.  On  passenger  trains 
equipped  with  the  air  signal,  the  signal  for  releasing  after 
a  test  should  be  given  with  the  car  discharge  valve  from 
the  rear  platform  of  the  last  car. 

99.  Q.  How  can  the  piston  travel  on  a  freight  car  be 
tested  and  then  taken  up  the  proper  length  when  car  is  not 
charged  with  air  and  brake  operated? 

A.  See  that  the  push  rod  going  from  piston  to  brake 
cylinder  lever  is  clear  in  against  the  bottom  of  piston  sleeve. 
Make  a  mark  on  the  push  rod  even  with  end  of  the  sleeve. 
Set  the  brake  by  hand  as  tight  as  possible,  with  a  club  if 
necessary;  the  distance  push  rod  is  pulled  out  of  sleeve  is 


132  DEFECTIVE   BRAKES 

the  piston  travel.  There  is  generally  over  an  inch  more 
piston  travel  when  car  is  moving  than  when  standing;  it 
is  more  with  heavy  braking  power  on  a  car  than  with  light. 
The  piston  travel  on  an  empty  car  may  be  very  short,  say 
four  inches,  and  when  loaded  the  same  car  may  have  nine 
inches.  When  testing  from  the  engine,  have  the  brakes 
set  with  full  service  application,  so  you  will  get  full  piston 
travel. 

100.  Q.  If  the  brake  sets  tight  when  you  are  charging 
the  auxiliary  reservoir  with  air  when  first  coupling  the 
hose  to  another  car,  should  you  cut  out  that  brake? 

A.  If  it  is  a*  quick  action  triple  it  is  a  sign  that  air 
leaks  through  some  of  the  joints  or  valves  in  the  triple  into 
the  brake  cylinder.  Have  the  engineer  set  and  release  the 
brake  suddenly,  once  or  twice;  if  there  is  dirt  on  the  rub- 
ber seat  of  the  emergency  valve  which  causes  the  trouble, 
it  will  sometimes  blow  it  off;  if  it  does  not  make  the  brake 
work  all  right,  very  likely  some  of  the  gaskets  are  leaking 
badly ;  in  such  a  case  cut  it  out  and  bleed  it.  With  the 
freight  brake  there  may  be  a  leak  in  the  pipe  from  the 
triple  valve  to  the  brake  cylinder  which  passes  through 
the  auxiliary  reservoir,  nothing  can  be  done  on  the  road 
for  a  leak  of  this  kind  but  cut  out  the  brake.  Most  always 
in  these  cases  the  air  blows  out  of  exhaust  port  or  at  the 
pressure  retaining  valve.  With  the  plain  triple  the  plug 
cock  in  triple  may  be  turned  out  for  "straight  air."  This  will 
allow  the  air  to  go  direct  from  train  pipe  to  brake  cylinder ; 
none  of  it  will  come  out  of  exhaust  port,  as  the  triple  is 
cut  out  from  train  pipe  and  cylinder.  In  this  case  cut  it 
in  for  automatic.  If  the  handle  is  gone,  or  put  on  wrong, 
examine  the  marks  on  the  end  of  plug  which  show  which 
way  the  air  openings  are  and  you  will  know  which  way  to 
turn  the  plug.  If  this  plug  cock  leaks,  the  air  can  get 
past  it  from  train  pipe  to  brake  cylinder.  If  brake  will  not 
work  after  one  or  two  applications,  cut  it  out.  With  all 
plain  triples  the  brake  should  be  released  first,  although 
the  plain  triple  used  on  freight  equipment  is  built  to  bleed 
the  brake  cylinder  when  brake  is  cut  out.  Sometimes  this 


PISTON    TRAVEL  133 

bleed  hole,  which  is  in  one  side  of  plug  cock  in  the  plain 
freight  triple  valve,  gets  stopped  up,  in  which  case  it  may 
be  necessary  to  let  all  the  air  out  of  the  train  pipe — set 
this  triple  for  straight  air  which  will  bleed  brake  cylinder, 
after  which  cock  in  triple  can  be  placed  in  cut  out  position. 

101.  Q.     If  the  piston  travel  is  too  long  or  too  short 
what  effect  does  it  have  on  the  brake  as  to  its  holding 
power? 

A.  If  it  is  too  short  it  will  not  cover  the  leakage 
groove,  and  air  will  leak  out  of  cylinder;  it  must  travel 
three  inches  to  cover  this  groove.  If  it  is  too  long  it  will 
strike  the  cylinder  head,  which  will  get  the  force  instead 
of  the  brake  shoes ;  it  must  travel  twelve  inches  to  do  this. 
All  brake  pistons  on  coach,  freight  and  tender  equipment 
of  standard  gage  have  12-inch  piston  stroke,  but  should 
not  have  over  8  or  9  inches  piston  travel.  The  piston 
travel  should  be  adjusted  equally  so  the  braking  power  will 
be  equal  on  all  cars.  Unequal  piston  travel  gives  un- 
equal braking  power.  This  is  the  cause  of  many  severe 
shocks  to  long  trains  when  first  applying  the  brakes,  and 
still  more  severe  shocks  when  releasing  the  brakes  at  a 
slow  speed.  For  instance  if  some  of  the  brakes  have  only 
five  inches  piston  travel,  when  the  engineer  makes  the 
first  reduction  of  train  pipe  pressure  to  apply  the  brakes, 
those  with  short  travel  will  set  hard  enough  to  take  up  the 
slack  of  train  quicker  than  the  other  brakes  with  long 
piston  travel.  A  first  reduction  in  applying  the  brakes  is 
at  least  seven  pounds,  less  than  this  will  not  apply  all  the 
brakes  on  a  long  train.  This  will  give  a  pressure  of  twenty- 
three  pounds  on  the  piston  with  five-inch  travel,  eight 
pounds  on  one  with  nine  inches  travel,  one  with  ten  inches 
travel  will  not  show  any  pressure  at  all,  the  shoes  will  just 
come  nicely  up  to  the  wheels.  A  few  short  travel  brakes 
can  give  serious  shocks  in  a  train  that  are  plainly  felt  at 
the  rear  end. 

102.  Q.     If  air  blows   past  piston  packing  so   freight 
brake  leaks  off,  can  it  be  fixed  on  the  road? 

A.     Sometimes  this  is  from  want  of  oil  in  the  cylinder; 


134  LEAKY    PISTON    PACKING 

if  the  oiling  plug  near  back  cylinder  head  where  it  makes 
a  joint  with  cast  iron  auxiliary  reservoir  is  taken  out  and 
four  or  five  tablespoonsful  of  black  oil  put  in,  it  will  soften 
the  packing  so  it  will  be  tight.  The  piston  sleeve  should 
then  be  turned  around  one-half  turn  to  bring  the  softened 
packing  to  the  top  of  the  cylinder.  This  should  be  at- 
tended to  by  car  inspectors,  but  is  not  always  done.  In 
no  case  should  oil  or  water  be  put  in  the  hose  and  be 
blown  back  into  the  triple  with  the  air.  It  will  carry  the 
dust  and  sand  back  in  the  pipe  towards  the  triple;  this 
stops  up  the  strainers,  and  if  any  gets  by  the  strainers  it 
spoils  the  rubber  seat  of  the  emergency  valve,  and  cuts  the 
triple  to  pieces  very  fast.  Putting  oil  in  the  hose  will 
destroy  the  efficiency  of  the  brake  in  very  short  time. 

103.  Q.  How  can  the  air  signal  whistle  be  operated 
from  the  cars  most  successfully? 

A.  By  allowing  just  enough  air  to  escape  at  the  car 
discharge  valve  to  reduce  the  air  signal  line  pressure  clear 
to  signal  valve  on  engine,  so  that  it  will  operate  promptly, 
then  allowing  car  discharge  valve  to  close  and  remain 
closed  till  signal  line  is  recharged  to  standard  pressure; 
this  sometimes  takes  two  seconds.  A  heavier  reduction 
with  a  longer  interval  between  pulls  is  needed  for  a  very 
long  train  than  a  short  one.  The  whistle  will  give  only 
one  blast  if  the  car  discharge  valve  is  opened  a  second  and 
third  time  before  the  whistle  stops  blowing  the  first  time. 

If  you  make  a  second  and  third  reduction  before  the 
reducing  valve  on  engine  has  had  time  to  charge  signal 
line  to  standard  pressure,  the  second  and  third  blasts  of 
whistle  will  be  very  weak;  in  cold  weather  the  reducing 
valves  do  not  always  work  perfectly.  Sometimes  when  a 
car  discharge  valve  is  opened,  a  sufficient  amount  of  air 
will  seem  to  blow  out  there,  but  on  account  of  an  obstruc- 
tion near  the  train  pipe  Tee  under  car  it  does  not  reduce 
the  pressure  enough  at  the  engine  to  operate  the  signal 
valve,  and  the  whistle  cannot  be  operated  from  that  car 
when  it  works  from  other  cars.  If  the  whistle  blows  once 
when  engine  is  coupled  to  train  and  cannot  be  sounded 
afterward,  look  for  a  bad  leak  near  rear  end  of 


OPERATING  THE  AIR   SIGNAL  135 

If  the  whistle  cannot  be  sounded  from  any  cars  back  of 
a  certain  car,  the  cock  in  back  end  of  that  car  is  shut,  or 
train  pipe  is  stopped  up  so  you  cannot  make  a  sudden 
enough  reduction  there  to  affect  the  signal  valve  on  the 
engine.  If  one  blast  of  the  whistle  is  used  to  start  the 
train  without  using  any  additional  signal,  remember  that 
one  blast  of  the  whistle  can  be  given  (without  opening  car 
discharge  valve)  when  you  do  not  want  the  train  started. 
For  instance,  if  the  signal  hose  has  been  uncoupled  (with- 
out the  knowledge  of  the  engineer)  for  any  purpose;  when 
the  cock  is  opened  enough  air  goes  into  empty  hose  to 
sound  the  whistle,  giving  signal  to  start  the  train  before 
the  man  coupling  hose  can  get  out  from  between  coach 
platforms.  Other  causes  may  cause  the  whistle  to  give 
one  blast  when  not  intended,  therefore  it  is  not  always 
safe  to  use  one  blast  of  the  whistle  when  standing  still,  to 
start  the  train. 

104.  Q.    If  hand  brakes  are  used  on  part  air  train,  on 
which  cars  should  they  be  used? 

A.  On  the  cars  next  behind  the  air  braked  cars  so  the 
hand  brakes  will  hold  these  cars  and  prevent  slack  running 
out  of  rear  cars  when  air  brakes  are  released.  In  case  of 
an  emergency  all  hand  brakes  should  be  set  on  cars  that 
do  not  have  air  brakes  working.  Care  should  be  taken 
that  hand  brakes  are  released  on  rear  end  of  a  part  air 
train  first,  air  brakes  last,  when  running  forward  and  in 
the  reverse  manner  when  backing  a  train. 

105.  Q.    On  an  air  braked  passenger  train  in  case  the 
engineer  whistles  for  brakes  what  is  the  trainmen's  duty? 

A.  Open  the  conductor's  valve  first.  An  angle  cock 
may  be  closed  which  prevents  the  engineer  applying  all 
the  brakes.  If  the  air  escapes  freely  and  the  brake  goes 
on  let  the  hand  brakes  alone.  If  no  air  escapes  from  train 
pipe  the  brake  may  have  already  been  set.  Try  the  hand 
brakes  last,  if  the  brake  is  set  with  air  pressure  you  can 
not  move  it  by  hand.  If  it  is  not  set  with  air  you  can  set 
it  by  hand,  the  air  may  have  leaked  out  of  cylinder. 

106.  Q.    How  do  leaks  affect  the  operation  of  the  brake 
on  a  car  or  coach? 


136  LEAKY    AND    STICKING    BRAKES 

;.  A.  If  the  train  pipe  leaks  the  brake  will  continue  to 
set  tighter  after  the  first  reduction  till  full  set.  This  leak 
affects  a  single  car  or  a  short  train  more  than  a  long  train, 
as  a  short  train  pipe  has  less  volume  of  air  to  leak  out. 

A  leak  from  the  train  pipe  past  the  seat  of  the  emer- 
gency valve  will  allow  the  train  pipe  air  to  equalize  with 
the  brake  cylinder  when  the  brake  is  applied  so  the  triple 
slide  valve  has  closed  the  exhaust  port;  this  may  stick 
this  brake  especially  if  the  triple  piston  packing  ring  also 
leaks. 

Any  leak  from  the  auxiliary  which  makes  that  pressure 
less  than  the  train  pipe  will  move  the  triple  to  exhaust 
position;  the  air  in  cylinder  will  escape  through  exhaust. 
With  a  leaky  packing  leather  the  air  will  blow  past  it, 
coming  out  around  the  piston  rod  or  sleeve;  none  will 
come  out  of  the  exhaust. 

107.  Q.     Where  should  you  look  for  the  trouble  if  the 
brake  applied  properly  but  would  not  release  ? 

A.  Very  likely  the  pressure  retaining  valve  was  closed ; 
examine  it  first  to  be  sure  it  is  open.  On  some  sleepers 
and  official  cars  both  the  triple  valve  and  retainer  are  con- 
cealed by  the  reservoirs  and  lockers,  so  it  is  necessary  to 
hunt  them  up,  beginning  with  the  triple  exhaust,  and  if 
any  pipe  is  attached  following  it  up.  If  the  retainer  pipe 
is  stopped  up  or  plugged  no  air  can  come  out  of  triple 
exhaust.  In  cold  weather  the  water  from  drip  valves  of 
steam  heated  cars  may  splash  over  the  exhaust  ports  of 
triple  valve  and  freeze  on;  this  may  stop  up  the  exhaust. 

Levers  or  rods  may  catch  on  bolt  heads  or  other  projec- 
tions under  the  car  and  hold  the  brake  after  the  air  has 
exhausted  from  cylinder.  If  the  release  spring  in  cylinder 
is  broken  the  piston  will  not  move  back.  Stopped  up 
strainers  at  the  triple  have  been  known  to  prevent  release 
of  brake ;  air  would  pass  out  of  valve  but  could  not  return 
quickly. 

108.  Q.     In    case    a   brake    is    noticed   to   be    sticking 
regularly,  can  you  help  it  to  release  at  the  same  time  the 
others  do? 


WATER  RAISING    SYSTEM 


137 


A.  Short  piston  travel  may  cause  this  trouble.  B^ 
extending  the  piston  travel  it  will  lower  the  auxiliary 
pressure  on  a  full  application  so  the  triple  is  more  likely 
to  move  up  promptly.  As  brakes  are  more  apt  to  stick  on 

WATER,PRESSURE  GOVERNOR 
VALVE. 


the  rear  of  a  long  train  than  when  next  the  engine,  this 
car  can  be  set  ahead  if  necessary  to  use  its  brake. 

Leaky  triple  packing  rings  and  choked  strainers  will 
also  cause  this  trouble.  Better  cut  out  the  brake  than  risk 
spoiling  the  wheels.  Report  this  defect  to  the  proper 
party. 


138  WATER   RAISING    SYSTEM 

109.  Q.  How  does  the  water  raising  system  used  on 
Pullman  cars  operate? 

A.  This  system  has  so  many  modifications  and  is  so 
complicated  that  a  full  description  cannot  be  given  here. 
There  is  an  air  reservoir  which  is  charged  with  air  up  to 
train  pipe  pressure,  sometimes  directly  from  the  train  pipe ; 
at  other  times  from  the  brake  auxiliary  reservoir;  the 
latest  method  being  to  take  air  from  the  brake  auxiliary. 
To  regulate  the  flow  of  air  into  this  air  storage  reservoir 
there  is  a  governor  and  non-return  check  valve;  the  latest 
pattern  of  which  is  here  shown.  The  governor  operates 
exactly  like  an  air  pump  governor  and  should  be  set  at 
sixty  pounds  so  it  will  not  interfere  with  the  air  brake 
pressure  when  that  is  below  sixty  pounds.  In  this  same 
valve  is  a  non-return  check  38  to  prevent  air  coming  back 
from  the  air  storage  reservoir,  the  stem  of  which  is  made 
a  neat  fit  at  h  so  the  air  will  feed  past  it  slowly  and  not 
take  air  too  fast.  Between  the  air  storage  reservoir  and 
the  water  reservoirs  is  a  reducing  valve  similar  to  the  .one 
used  with  the  air  signal,  set  at  twenty  pounds,  which  pres- 
sure is  sufficient  to  give  a  good  flow  of  water  to  the  basins. 
If  this  reducing  valve  is  set  at  too  high  a  pressure  or  gets 
dirty  or  stuck  open  so  it  does  not  operate,  the  full  pressure 
of  the  storage  reservoir  will  be  in  the  water  tanks,  which 
not  only  uses  too  much  air  but  is  liable  to  splash  the  water 
all  over  the  basins  when  faucet  is  opened.  The  pressure 
in  the  water  tanks  operates  this  reducing  valve.  When 
the  tanks  are  to  be  refilled  the  air  supply  is  shut  off,  that 
in  the  tanks  is  allowed  to  escape  and  water  put  in.  When 
air  comes  out  into  the  basins  with  the  water  it  is  a  good 
sign  the  water  is  nearly  gone.  If  no  water  or  air  comes 
out  when  you  are  sure  there  is  a  proper  air  pressure, 
examine  the  numerous  cocks  to  see  if  any  of  them  are 
closed.  As  the  cars  are  not  all  piped  exactly  alike  it  is 
usually  necessary  to  trace  the  pipes  up  and  locate  the  stop 
cocks  and  valves  when  making  an  inspection.  There  are 
also  heating  pipes  connected  with  the  devices  of  the  water 
raising  system  to  prevent  freezing  up.  Gages  are  usually 
located  up  in  the  cars  which  show  the  air  pressure  in  the 


WATER   RAISING    SYSTEM  139 

storage  reservoir  and  water  tanks,  70  in  the  former  after 
charging  fully,  and  20  in  the  water  tanks.  Suitable  cocks 
under  control  of  the  porters  are  provided  to  open  or  close 
the  passage  of  air  from  brake  system  to  the  water  raising 
system  with  a  code  of  rules  for  operating  .these  cocks. 

no.  Q.  How  does  this  water  raising  system  affect  the 
operation  of  the  brake? 

A.  When  air  is  passing  from  train  pipe  or  auxiliary  to 
air  storage  reservoir  it  takes  a  little  time  to  charge  the 
storage  reservoir.  If  at  that  time  brake  is  applied  as  when 
making  a  terminal  test  of  train  brakes,  air  passing  from 
the  train  pipe  will  set  the  brakes  tighter;  if  it  goes  from 
the  brake  auxiliary  it  will  likely  release  that  brake, 
especially  if  set  with  a  light  application.  If  the  non-return 
check  valve  leaks  back  after  air  storage  reservoir  is  fully 
charged,  this  air  can  flow  in  the  train  pipe  if  so  connected 
and  release  all  the  train  brakes.  If  the  connection  is  made 
to  the  brake  auxiliary,  a  leaky  check  valve  will  allow  the 
volume  of  the  storage  reservoir  to  be  added  to  that  of  the 
auxiliary  and  skid  the  wheels  on  a  full  application. 
If  all  the  stop  cocks  are  not  properly  operated  and  the 
valves  in  good  order  the  work  of  the  brake  may  be  inter- 
fered with,  which  shows  that  it  is  absolutely  necessary 
that  they  should  be  inspected  at  regular  intervals  by  com- 
petent men  and  be  maintained  in  proper  order.  If  the 
governor  which  restricts  the  flow  of  air  from  the  brake 
system  is  in  perfect  order  and  set  at  the  proper  pressure, 
unless  a  large  amount  of  air  is  used  by  the  water  system, 
the  operation  of  the  brake  will  not  be  materially  affected. 
If  air  is  taken  from  the  brake  system  during  the  applica- 
tion of  the  brake  it  is  sure  to  affect  the  work  of  the  triple 
valve,  either  to  apply  the  brake  harder  or  release  it. 

The  wide  spread  use  of  this  system  requires  that  coach 
inspectors  inform  themselves  as  to  its  construction  and 
operation,  and  that  train  men  and  porters  comply  strictly 
with  the  rules  for  its  operation. 

in.  Q.  Can  you  get  the  emergency  action  of  the 
brake  with  the  pressure  retainer  holding  15  pounds? 

A.    Yes;  if  the  triple  is  in  exhaust  position,  with  train 


I4O  RETAINING  VALVES 

pipe  and  auxiliary  equalized  at  70  pounds,  when  a  sudden 
reduction  of  train  pipe  pressure  is  made,  it  will  move  the 
triple  piston  full  stroke,  opening  the  emergency  port. 
With  air  at  70  pounds  pressure  in  auxiliary  the  emergency 
^piston,  having  only  15  pounds  pressure  under  it,  will  be 
forced  down  at  once,  the  train  pipe  air  pressure  will  still 
be  so  much  above  15  pounds  that  train  pipe  air  will  flash 
into  the  brake  cylinder,  and  this  sudden  reduction  made 
by  the  triple  will  affect  the  next  triple  so  it  will  work 
quick  action  also.  Question  49  explains  why  quick  action 
can  not  be  had  after  a  moderate  service  application.  The 
use  of  retainers  interferes  so  little  with  the  quick  action 
that  the  emergency  action  will  jump  over  as  many  cars 
with  the  brakes  cut  out  at  the  cross-over  cocks  with  all 
retainers  holding  15  pounds  as  when  retainers  are  not 
being  used,  provided  the  triple  valve  starts  from  exhaust 
position  and  auxiliary  recharged  to  70  pounds. 


THE  HIGH  SPEED  BRAKE. 

This  improvement  on  the  quick-action  automatic  brake 
for  passenger  equipment  is  designed  to  enable  the  engineer 
to  apply  the  brake  as  is  ordinarily  done  in  service  applica- 
tions, or  in  case  of  an  emergency  with  the  train  running 
at  a  high  speed,  to  apply  it  with  a  higher  force  which  can 
be  proportioned  to  the  speed  of  the  train. 

For  ordinary  speed,  below  thirty  miles  an  hour,  the  70 
pound  automatic  brake  is  able  to  control  the  train  in  the 
ordinary  manner,  but  when- the  speed  is  much  higher,  more 
power  is  required  in  proportion  as  the  speed  is  higher.  It 
is  the  friction  of  the  brake  shoes  on  the  wheels  that  arrests 
the  speed  of  the  train  and  finally  brings  it  to  a  stop.  In 
addition  to  arresting  the  momentum  of  the  train  this  fric- 
tion must  also  arrest  the  rotary  motion  of  the  wheels 
turning  around  at  high  speed ;  this  takes  considerable  brake 
power.  There  is  a  difference  in  the  amount  of  the  friction 
of  the  same  shoes  and  wheels  at  different  speeds,  it  being 
greater  at  a  low . speed  than.at  a  high  one. 


FRICTION    AND   BRAKE   POWER  14! 

What  is  called  the  co-efficient  of  friction,  which  is  the 
proportion  between  the  brake  power  applied  to  the  shoes 
and  their  holding  power,  is  about  .074  at  sixty  miles  an 
hour,  increasing  to  .241  as  the  speed  is  reduced  to  ten 
miles  an  hour,  to  .273  at  five  miles  an  hour  and  just  as  the 
final  stop  is  made  it  is  .330,  so  you  see  the  brake  shoes  * 
really  hold  less  at  a  high  speed  than  at  a  low  one,  anct 
more  brake  power  can  be  applied  at  the  high  speed  than 
could  be  safely  used  at  a  low  one  arid  make  the  holding 
power  about  right  for  each  speed. 

Now  it  follows  that  if  the  full  brake  power  was  the 
same  for  all  speeds,  if  it  was  the  proper  power  for  a  mod- 
erate speed  it  would  be  much  too  low  for  a  high  speed.  If 
a  high  speed  was  the  standard  the  full  brake  power  would 
be  too  high  for  the  low  speed,  the  wheels  would  skid  on 
the  rail  and  a  loss  of  about  one-third  of  the  brake  power 
would  result.  This  would  allow  the  train  to  run  consider- 
able farther  than  if  the  wheels  were  held  back  by  the  shoes 
just  up  to  the  sliding  point — without  sliding. 

Therefore,  an  attachment  to  the  brake  that  would  give 
a  very  high  brake  power  when  first  applied  while  running 
at  a  very  high  speed  and  gradually  reduce  this  brake  power 
at  about  the  same  rate  the  speed  was  reduced,  would  be 
proper  for  all  speeds. 

This  brake  power  for  moderate  speeds  has  usually 
been  fixed  at  90  per  cent,  of  the  weight  of  the  coach  when 
all  the  wheels  have  brake  shoes  applied  to  them,  and  is 
about  all  that  can  be  used  without  sliding  the  wheels  just 
as  the  final  stop  is  made. 

This  reduction  of  10  per  cent,  from  the  total  load  on 
the  wheels  with  brake  shoes  applied  is  not  exactly  correct 
for  both  light  and  heavy  cars.  If  10  per  cent,  of  the  weight 
of  a  car  weighing  50,000  pounds  is  a  proper  reduction  to 
prevent  wheel  sliding,  then  the  same  number  of  pounds 
reduction,  i.  e.,  5,000  pounds  should  be  enough  for  a  car 
weighing  100,000  pounds.  The  old  90  per  cent,  rule  would 
give  10,000  pounds  as  the  amount  for  this  car,  or  5,000 
pounds  more  than  needed.  Therefore,  to  get  the  best  ser- 


HIGH  SPEED  BRAKE  AUTOMATIC  REDUCING  VALVE 
FOR  PASSENGER  EQUIPMENT  CARS  AND  LOCOMOTIVES 
PLATE  F  45.    (1898  Pattern). 


fdcmoN  or  POUT*,' 
CHtitacNev  STOP.    - 


EMERGENCY    BRAKE    POWER  143 

vice  the  same  amount  of  reduction  in  pounds  should  be 
made  from  all  cars  braked  to  the  same  per  cent. 

For  emergency  action  the  high  speed  brake  is  intended 
to  apply  the  brakes  at  first  with  a  brake  power  of  125  per 
cent,  of  the  weight  of  the  coach  and  gradually  reduce  the 
brake  cylinder  pressure  as  the  speed  is  reduced,  till  it 
reaches  the  standard  amount  of  sixty  pounds,  which  gives 
a  90  per  cent,  brake  power,  at  which  point  the  reduction 
ceases,  leaving  the  cylinder  pressure  at  the  amount  and 
the  braking  power  at  the  percentage,  at  which  the  wheels 
will  not  slide  when  the  car  is  about  to  stop. 

To  get  this  increased  brake  power  the  train  pipe  and 
auxiliary  pressure  is  increased  to  no  pounds.  With  an 
emergency  application  the  pressure  at  first  is  about  eighty- 
five  pounds.  The  brake  cylinder  pressure  is  reduced  by 
an  automatic  reducing  valve,  which  is  here  illustrated. 

This  reducing  valve,  the  latest  pattern  of  which  is 
shown  in  Fig.  i,  is  fastened  by  the  bracket  at  x  to  the 
coach  frame  (see  Fig.  6)  and  connected  to  the  brake  cyl- 
inder by  suitable  piping  at  z  (see  Fig.  2).  When  the  air 
enters  the  cylinder1  at  the  time  the  brakes  are  applied,  it 
also  comes  in  on  top  of  piston  4.  This  piston  is  held  up 
by  the  spring  u  against  a  pressure  of  sixty  pounds  per 
inch,  so  that  if  no  more  than  sixty  pounds  comes  into  the 
cylinder  the  reducing  valve  remains  stationary  in  the 
position  shown  in  Fig.  3. 

It  should  be  noted  that  the  area  of  the  reducing  valve 
piston  4  that  the  brake  cylinder  air  presses  against  is 
slightly  less  when  the  gasket  20  is  up  solid  to  the  shoulder 
of  the  bushing  e  than  after  it  is  moved  down. 

When  a  graduated  service  application  is  made,  if  the 
brake  cylinder  pressure  raises  above  sixty  pounds  the  pis- 
ton 4  is  moved  down  far  enough  to  open  the  triangular 
port  b  in  the  slide  valve  8  to  exhaust  port  a  in  the  seat  so 
that  the  widest  part  of  port  b  is  open  as  shown  in  Fig.  4. 
The  air  can  then  pass  out  of  the  brake  cylinder  about  as 
fast  as  it  comes  in  through  the  graduating  valve  of  the 
triple ;  when  the  brake  cylinder  pressure  drops  below  sixty 


144 


OPERATION  OF  REDUCING  VALVE 


POSITION  or  PORT*. 
•CMVICC  STO 

PftCMUNK  CXCCKDINA  CO  POUND* 
.IN  BRAKE  CYUNDCft. 


pounds  the  spring  under  piston  4  moves  slide  valve  8  up 

and  laps  ports  a  and  b,  as 
shown  in  Fig.  3,  and  no 
more  air  can  escape. 

In  case  an  emergency 
application  is  made  the 
brake  cylinder  pressure 
rises  like  a  flash  up  to 
eighty-five  pounds,  piston  4 
i  s  forced  down  a  t  once 
against  the  tension  of  the 
spring  to  the  lower  limit 
its  travel  into  the  posi- 
tion  shown  in  Fig.  5.  This 
pulls  slide  valve  8  clear 
down,  the  small  end  of  the 
triangular  port  b  is  open  to 

port  a,  and  the  brake  cylinder  air  escapes  slowly  to  the 
atmosphere.  As  the  pressure  is  reduced  the  spring  n  has 
power  to  move  piston  4  up  and  the  triangular  port  b  opens 
wider  which  reduces  the  brake  cylinder  pressure  faster, 
down  to  sixty  pounds;  at  which  point  the  slide  valve  is 
moved  up  to  lap  ports  a  and  b  so  no  more  air  can  escape 
from  brake  cylinder,  this  position  is  shown  in  Fig.  3. 

The  size  of  this  exhaust  port  b  has  been  determined  by 
experiments  so  as  to  reduce  the  brake  cylinder  pressure 
proportionate  to  the  reduction  in  speed.  It  is  a  different 
size  for  each  size  of  reducing  valve  to  suit  the  different 
volumes  of  air  which  should  pass  out  of  small  and  large 
cylinders  in  about  the  same  time. 

With  a  service  application  the  reducing  valve  reduces 
the  brake  cylinder  pressure  only,  as  the  triple  valve  closes 
the  air  port  from  the  auxiliary.  With  an  emergency  appli- 
cation where  the  train  pipe  pressure  drops  below  sixty 
pounds  the  triple  holds  the  air  port  open  and  the  reducing 
valve  has  to  reduce  both  brake  cylinder  and  auxiliary 
volumes  to  sixty  pounds. 

When  the  brake  is  first  set  with  emergency  at  a  high 


OPERATION    OF   REDUCING   VALVE  145 

speed  the  pressure  is  about  eighty-five  pounds  in  the  cyl- 
inder; as  the  speed  of  the  train  is  reduced  by  the  action  of 
the  brakes,  the  pressure  is  also  reduced  by  the  reducing 
valve  at  about  the  same  rate,  till  it  reaches  sixty  pounds, 
where  it  remains  till  the  brake  is  released  in  the  regular 
way. 

After  an  emergency  application  the  reducing  valve  low- 
ers the  cylinder  pressure  very  slowly  at  first  through  the 
small  pointed  end  of  the  port  b,  and  faster  as  the  pressure 
drops  till  it  reaches  60  pounds,  when  the  valve  closes.  The 
speed  of  the  train  is  reduced  by  the  action  of  the  brakes 
slowly  at  first,  and  the  reduction  of  speed  is  more  marked 
each  succeeding  second  of  time  till  when  nearly  at  a 
stop  the  speed  is  reduced  very  fast.  The  pressure  is  re- 
duced at  about  the  same  ratio  as  the  speed,  so  as  to  have 
it  reach  60  pounds  at  about  the  time  when  60  pounds  will 
do  the  work  properly. 

This  gives  a  very  high  brake  power  ready  to  use  if 
found  necessary  at  high  speeds  and  still  leaves  the  service 
application  feature  unchanged,  ready  for  use  in  ordinary 
stops.  With  the-  service  application  the  reducing  valve  re- 
mains in  position  as  shown  in  Fig.  3.  A  reduction  of 
twenty  pounds  from  no  applies  the  brake  fully,  as  this 
reduction  will  fill  the  brake  cylinders  at  fifty  pounds,  the 
full  pressure  of  an  ordinary  service  application;  as  well  as 
leaving  a  high  auxiliary  reservoir  pressure  of  ninety 
pounds  ready  for  two  more  full  service  applications  of 
the  brake  if  found  necessary  before  re-charging;  during 
these  moderate  service  applications  the  reducing  valve  does 
not  move. 

The  train  pipe  and  auxiliary  pressure  is  set  at  no 
pounds  with  this  type  of  brake — it  may  be  more  if  the  con- 
ditions seem  to  call  for  it.  As  the  engines  equipped  for 
drawing  these  high  speed  braked  trains  may  be  used  to 
draw  coaches  without  the  high  speed  attachments,  some 
arrangement  is  needed  for  changing  the  standard  train 
pipe  pressure  from  no  pounds  to  the  lower  pressure  and 
vice  versa.  For  this  purpose  there  are  two  feed  valve  at- 


146  ENGINE    BRAKE    DETAILS 

tachments  on  the  engine.  One  of  them  is  set  at  70  pounds, 
the  other  at  no,  and  there  is  a  reversing  cock  between 
them  which  can  be  turned  to  "  cut-in  ""  either  one  for  ser- 
vice as  is  desired,  only  one  being  operated  at  a  time. 
This  reversing  cock  and  valves  are  coupled  to  the  brake 
valve  with  suitable  piping.  Likewise  there  is  a  duplex  gov- 
ernor for  the  air  pump,  one  side  of  which  is  set  for  ninety 
pounds  main  reservoir  pressure,  for  the  ordinary  70 
pounds  train  pipe  pressure,  the  other  side  set  at  the  higher 
pressure  required,  and  a  suitable  cock  to  cut  out  the  ninety 
pound  side  when  using  the  higher  pressure.  As  these  high 
speed  trains  are  usually  short,  ten  pounds  excess  has  been 
found  sufficient,  but  more  is  needed  with  a  longer  train;  in 
some  cases  30  pounds,  in  order  to  be  sure  to  release  all 
brakes,  after  a  light  application.  The  tender  is  equipped 
with  a  quick-action  triple  and  reducing  valve  the  same  as 
a  coach.  An  engine  truck  brake  is  a  necessary  part  of  this 
equipment,  which  is  supplied  with  air  from  the  driver 
brake  triple;  a  reducing  valve  similar  to  the  coaches  is 
used,  set  at  fifty  pounds.  Any  extra  coaches  placed  on 
these  high  speed  braked  trains  require  a  reducing  valve, 
although  a  safety  valve  set  to  blow  off  at  sixty  pounds 
through  a  restricted  opening  can  be  used  temporarily  by 
screwing  it  into  the  oiling  plug  hole  in  the  cylinder  head. 
This  safety  valve  is  not  as  reliable  as  the  reducing  valve, 
and  is  only  used  as  a  temporary  relief. 

This  type  of  brake  will  stop  a  train  running  at  sixty 
miles  per  hour  in  about  450  feet  less  distance  than  the 
ordinary  quick-action  brake. 

After  a  full  emergency  application  with  no  pounds  train 
pipe  and  auxiliary  reservoir  pressure  the  maximum  brake 
cylinder  pressure  in  a  14-inch  cylinder  with  six  inches 
piston  travel  will  be  eighty-eight  pounds;  seven  inches 
travel  will  give  close  to  eighty-five  pounds.  If  at  this 
emergency  application  the  train  pipe  pressure  is  all  let  out 
or  reduced  below  sixty  pounds,  the  reducing  valve  will 
reduce  the  pressure  in  brake  cylinder  and  auxiliary  to  sixty 
pounds  in  from  twenty-seven  to  thirty-one  seconds.  With 


OPERATING  THE  HIGH    SPEED   BRAKE  147 

an  emergency  reduction  and  equalization  of  reservoir  and 
brake  cylinder  pressures  at  eighty-five  pounds  the  reduc- 
ing valve  will  reduce  the  brake  cylinder  pressure  in  from 
sixteen  to  twenty  seconds. 

In  making  a  graduated  service  application,  with  a  pres- 
sure of  sixty  pounds  in  the  brake  cylinder,  when  a  further 
service  reduction  of  train  pipje  pressure  is  made  the  cylin- 
der pressure  will  increase  but  slightly  above  sixty  pounds 
and  immediately  be  reduced  to  that  amount  unless  a  full 
continuous  service  reduction  is  made,  in  which  case  the 
pressure  may  rise  to  seventy-seven  or  eighty  pounds,  being 
soon  reduced  to  sixty  pounds  by  the  reducing  valve.  After 
a  cylinder  pressure  of  sixty  pounds  is  obtained,  a  full  ser- 
vice reduction  to  below  sixty  pounds  should  never  be  made 
except  at  high  speeds  in  an  emergency. 

A  high  speed  brake  train  is  handled  in  much  the 
same  manner  an  expert  engineer  handles  an  ordinary  pas- 
senger train  of  the  same  length.  Remember  that  air  at 
no  pounds  pressure  moves  through  the  air  ports  more 
rapidly  than  at  70  pounds,  so  when  listening  to  the  sound 
of  the  air  discharging  from  the  preliminary  and  train  pipe 
exhausts  watch  the  gage  closely.  To  make  the  brake  valve 
reduction  more  gradual  a  larger  brake  valve  reservoir  is 
now  used,  which  holds  about  812  cubic  inches.  The  older 
ones  hold  close  to  600  cubic  inches. 

A  20  pound  service  reduction  will  give  about  the  same 
brake  cylinder  pressure  from  no  pounds  that  it  does  from 
70,  i.  e.,  about  fifty  pounds. 

A  22  pound  service  reduction  will  give  close  to  60 
pounds  in  the  cylinder,  anything  over  that  may  be  wasted, 
as  the  reducing  valves  will  not  let  the  cylinder  pressure  rise 
above  60  pounds. 

With  no  pounds  on  the  back  of  the  slide  valve  at  the 
beginning  of  a  service  application  and  90  pounds  at  the 
time  of  a  release,  the  slide  valve  cannot  be  moved  as  easily 
by  the  triple  piston  as  when  the  pressures  are  70  and  50 
pounds,  and  it  will  take  more  change  of  pressures  each 
side  of  the  triple  piston  to  move  it. 


148  OPERATING   THE   HIGH    SPEED   BRAKE 

The  graduating  valve  has  no  such  frictional  resistance. 
Triple  valves  when  dirty,  or  when  they  need  oiling,  give 
more  trouble  with  no  pounds  than  with  70,  on  account  of 
the  increased  pressure  on  the  slide  valve  which  makes  them 
more  apt  to  work  quick  action  with  a  gradual  service  re- 
duction. For  that  reason  both  the  triple  valves  and  brake 
valve  must  be  kept  clean  and  well  oiled  and  good  stiff  ex- 
cess is  needed  with  a  long  train. 

When  coupling  to  a  train  having  no  pounds  train  pipe 
pressure  with  an  engine  carrying  70  and  90  pounds,  put 
the  brake  valve  on  lap  and  leave  it  there  till  the  no  pounds 
pressure  has  blown  down  to  70  pounds  and  the  reducing 
valves  on  the  cars  have  blown  down  to  60  pounds.  Then 
with  full  excess  go  to  full  release  and  the  brakes  should 
all  release. 

In  handling  any  very  long  passenger  train  a  straight 
air  brake  on  the  engine  and  tender  is  a  valuable  aid  in 
preventing  break-in-twos  or  serious  shocks  when  releas- 
ing at  a  slow  speed,  the  E.  T.  equipment  on  the  locomo- 
tive is  still  better. 

Unless  an  emergency  arises  requiring  a  very  sudden 
stop,  do  not  use  the  emergency  application  with  no 
pounds,  when  running  at  a  slow  speed,  say  below  twenty- 
five  miles  an  hour.  Unless  the  rail  conditions  are  perfect 
the  wheels  are  apt  to  slide;  this  will  increase  the  length 
of  the  stop.  When  an  emergency,  such  as  danger  to  life 
or  property,  confronts  you,  remember  that  all  the  brakes 
act  quickly  with  the  emergency  application — in  less  than 
three  seconds — which  they 'will  not  do  as  quickly  with  a 
service  application.  Difference  in  piston  travel  does  not 
affect  the  work  of  the  high  speed  brake  as  much  as  it  does 
the  70  pound  brake  with  full  service  applications.  As  soon 
as  the  reducing  valve  operates  it  equalizes  the  cylinder 
pressures  for  long  and  short  travels,  for  all  will  reduce  to 
the  same  final  pressures.  If  the  leverage  is  proper,  all  cars 
will  be  braking  alike.  One  of  the  best  preventives  of 
wheel  sliding  is  equal  and  maximum  brake  power  On  all 
the  cars,  tender  and  engine.  With  all  wheels  -holding  back 
alike  tests  show  that  wheel  sliding  is  rare. 


PLATE 


I: 


HIGH  PRESSURE  CONTROL. 

With  the  heavy  capacity  cars  now  in  general  use,  the 
empty  weight  of  the  car  on  which  the  braking  power  is 
calculated  is  such  a  small  proportion  of  the  full  loaded 
weight  that  some  provision  must  be  made  to  increase  the 
braking  power  on  the  loaded  cars.  This  is  particularly 
the  case  with  coal  and  ore  cars,  which  usually  run  empty 
to  the  mines  and  return  loaded.  For  this  class  of  cars  a 
two-pressure  system  has  been  devised  in  which  a  moder- 
ately low  pressure  of  55  to  65  pounds  is  carried  in  the  train 
pipe  and  auxiliaries  of  the  empties,  while 
with  the  loaded  trains  90  pounds  can  be 
carried  and  thus  increase  the  brake  power 
about  50  per  cent.  The  duplex  governor 
and  reversing  cock  which  is  part  of  the 
High  Speed  Brake  is  used  with  the  High 
Pressure  Control,  but  the  duplex  governor 
is  piped  a  little  different.  There  are  two 
separate  pipes  leading  to  the  governor,  one 
from  the  main  reservoir  to  the  side  of  the 
governor  set  for  the  highest  pressure,  the 
other  pipe  leading  from  the  left  side  of  the 
reversing  cock,  which  is  set  for  the  lowest 
pressure,  to  the  low  pressure  side  of  the 
SAFETY  VALVE.  governor,  so  that  when  the  low  pressure 
feed  valve  is  cut  in,  the  low  pressure  governor  is  also 
cut  in. 

When  handling  a  train  of  empties  going  up  hill  the  low 
pressure  is  used,  coming  down  hill  with  a  train  of  loads 
the  high  pressure  is  used,  and  thus  the  train  can  be  con- 
trolled. Any  empty  cars  in  the  train  must  have  the  air 
brake  cut  out  at  cross-over  pipe  when  using  the  high 
pressure  to  avoid  sliding  wheels;  unless  the  caboose  has  a 
safety  valve,  it  must  be  cut  out  also. 

A  safety  valve  shown  on  this  page  is  attached  to  the 
brake  cylinders  of  the  engine  and  tender.  This  same  type 
of  valve  is  also  used  on  any  extra  coaches  set  in  a  High 
Speed  Brake  train. 


150  THE  AMERICAN  AUTOMATIC  SLACK  ADJUSTER 


THE  AMERICAN  AUTOMATIC   SLACK   ADJUSTER 


THE  AMERICAN  AUTOMATIC  SLACK  ADJUSTER. 

The  illustrations  of  the  American  Brake  Co.'s  Automatic 
Slack  Adjuster  show  how  the  adjuster  cylinder  and  ad- 
justing screw  is  attached  to  the  brake  cylinder  and  dead 
cylinder  lever.  A  small  port  is  drilled  and  tapped  in  the 
brake  cylinder  at  the  point  a  which  is  to  be  the  limit  of 
the  running  piston  travel.  A  pipe  E  is  connected  from 
this  port  o  to  the  adjuster  cylinder  at  G. 

The  brake  piston  acts  as  a  valve  to  admit  air  to  the 
adjuster  cylinder.  When  it  moves  beyond  port  a  during  a 
brake  application,  air  from  behind  the  brake  piston  passes 
out  of  port  a  through  the  pipe  E  into  the  slack  adjuster 
cylinder,  pushes  the  piston  to  the  left  against  the  strength 
of  the  spring  21,  carrying  the  pawl  22  out ;  spring  23  pushes 
the  pawl  down,  hooking  it  down  over  a  tooth  of  the  ratchet 
27.  When  the  brake  is  released  the  air  in  the  adjuster 
cylinder  passes  out,  spring  21  then  returns  the  adjuster 
piston  to  its  normal  position  which  pulls  back  pawl  22; 
this  rotates  ratchet  nut  27  on  the  screw  attached  to  the 
dead  cylinder  lever  fulcrum  jaw,  moving  the  end  of  the 
lever  up  l/32  of  an  inch,  taking  up  some  slack  in  the 
brake  rigging.  Tne  slack  is  not  taken  up  when  the  brake 
is  applied,  but  after  it  is  released,  when  there  is  no  strain 
on  the  cylinder  lever.  When  the  spring  pushes  back  the. 
piston  and  pulls  the  pawl,  the  lug  A  strikes  the  stop  B, 
this  raises  the  pawl  out  of  the  ratchet,  so  that  the  ratchet 
nut  can  be  turned  either  way,  if  the  adjuster  piston  is  in 


152  THE  AMERICAN  AUTOMATIC   SLACK   ADJUSTER 

normal  position,  this  will  allow  the  nut  to  be  turned  by 
hand  to  let  out  or  take  up  slack  in  brake  rigging  when  new 
shoes  are  put  on,  or  repairs  made  to  the  brake  gear.  In 
case  the  ratchet  nut  is  turned  on  its  screw  till  the  jaw  is 
pulled  up  solid  against  the  adjuster  cylinder,  the  pawl 
cannot  be  moved  far  enough  by  the  spring  21  to  have  the 
lug  A  strike  on  B;  in  which  event  the  casing  24  must  be 
opened  up  and  the  pawl  raised  out  of  the  ratchet  nut,  so  it 
can  be  turned  by  hand.  The  later  type  of  American 
Adjuster  has  a  stop  screw  located  near  the  adjuster  cylin- 
der, so  arranged  that  the  jaw  comes  in  contact  with  it 
instead  of  the  cylinder;  by  removing  this  screw  and  turn- 
ing the  ratchet  by  hand  the  pawl  is  released.  A  still  later 
type  has  a  tap  bolt  in  the  end  of  the  adjuster  nut  casing, 
slack  off  this  tap  bolt  and  the  screw  will  turn  a  little  more 
and  release  the  pawl.  The  pawl  and  ratchet  are  enclosed 
in  a  tight  case  to  keep  out  ice  and  foreign  matter  which 
would  prevent  their  movement. 

In  case  the  brake  piston  does  not  travel  to  port  a  the 
adjuster  does  not  move  any  of  its  parts,  but  is  at  rest.  If 
port  a  is  partially  or  fully  opened  by  the  piston,  which  acts 
as  a  valve,  compressed  air  is  admitted  to  the  adjuster 
cylinder,  so  it  is  operated. 

Slack  adjusters  take  up  the  travel  beyond  a  certain 
running  travel  limit.  The  brake  piston  will  travel  farther 
on  a  running  car  than  one  standing  still,  because  the 
journals  and  bearings  will  be  crowded  to  one  side  of  the 
oil  boxes  and  all  lost  motion  that  can  be  taken  up  in  the 
truck  comes  out  when  running.  For  that  reason  the  pis- 
ton travel  is  usually  found  to  be  less  when  measured  at  a 
standing  test  than  the  actual  distance  of  the  port  a  from 
the  pressure  head  of  the  cylinder.  If  this  port  a  is  eight 
inches  from  the  head  to  allow  eight  inches'  travel  it  is  not 
unusual  to  find  the  travel  at  a  standing  test,  less  than  six 
inches.  When  locating  port  a  first  see  how  for  the  edge 
of  the  piston  packing  leather  is  from  pressure  head  x. 
Port  a  is  very  small  where  it  comes  through  the  wall  of 
the  cylinder,  so  that  the  piston  packing  leather  will  not  be 
cut  when  passing  over  the  opening. 


TAKING    UP   THE   SLACK  153 

The  amount  of  slack  depends  on  the  brake  leverage. 
For  instance,  a  lo-inch  brake  cylinder  has  a  power  of 
4,700  pounds.  If  it  is  used  on  a  coach  weighing  52,220 
pounds,  90  per  cent,  of  this  weight  is  47,000  pounds,  so 
the  brake  power  required  at  the  shoes  is  ten  times  that  at 
the  piston,  or  a  total  leverage  of  10  to  i.  With  a  car 
weighing  36,550  pounds  the  brake  power  would  be  32,900 
or  a  total  leverage  of  7  to  i.  Now  with  the  same  amount 
of  slack  on  the  shoes  of  each  car  one  car  would  have  10 
inches  piston  travel,  the  other  would  have  only  7  inches. 
With  a  leverage  of  over  10  to  i  you  cannot  restrict  the 
piston  travel  to  6  inches  and  have  the  shoes  clear  the 
wheels  so  the  coach  will  pull  easy  between  the  stations. 

One  of  the  errors  made  when  taking  up  the  slack  by 
hand  is  using  the  shoe  clearance  instead  of  the  piston  travel 
as  a  guide.  With  a  light  car  and  large  cylinder,  where  the 
total  leverage  is  low,  there  will  be  considerable  clearance 
in  proportion  to  the  piston  travel.  If  the  slack  is  taken 
up  the  same  as  for  a  car  of  heavy  leverage,  the  brake  pis- 
ton will  not  pass  over  the  leakage  groove  with  moderate 
service  applications.  On  the  other  hand,  with  a  heavy  car, 
the  piston  may  bottom  on  the  cylinder  head.  For  this 
reason  a  device  that  will  regulate  the  piston  travel  while 
the  train  is  under  way  will  do  better  work  than  hand 
regulation. 

Uniform  piston  travel  is  one  of  the  prerequisites  of 
good  brake  service.  When  this  can  be  automatically  main- 
tained during  an  entire  trip  it  ensures  a  uniform  as  well 
as  a  maximum  efficiency  of  the  brakes.  If  this  adjustment 
is  made  by  hand  the  piston  travel  varies  considerable  on  a 
long  trip  with  a  corresponding  loss  of  efficiency. 

Unequal  piston  travel  is  the  cause  of  a  good  many  slid 
flat  wheels  in  coach  equipment,  and  is  responsible  for 
some  of  the  break-in-twos  in  long  freight  trains.  The 
braking  power  is  increased  by  short  travel  and  reduced  by 
long  travel,  so  that  a  coach  with  short  travel  may  have 
power  enough  to  slide  the  wheels  when  the  other  cars  do 
not  skid. 


BRAKE   LEVERAGE. 

Ability  to  figure  up  brake  leverage  is  an  accomplish- 
ment for  an  air  brake  operator — not  always  a  necessity — 
it  pays  to  know  something  definite  about  it.  The  rules 
are  not  complicated  and  formulas  help  to  shorten  the  cal- 
culations. You  should  first  learn  how  the  several  classes 
of  levers  operate  and  the  difference  between .  those  of  the 
first,  second  and  third  kind.  A  lever  of  the  first  kind  has 
the  power  applied  at  one  end,  the  weight  to  be  moved  is 
at  the  other  end  and  the  fulcrum  which  takes  both  the 
strain  of  the  power  and  the  resistance  of  the  weight  is  in 
between  the  ends ;  in  the  cut  of  a  lever  of  the  first  kind  F 
is  the  force  or  power  coming  from  the  top  rod,  C  in  the 
middle  is  the  fulcrum  and  W  at  the  bottom  is  the  brake 
beam  or  weight  to  be  moved.  The  cylinder  lever  connected 
to  the  brake  piston  is  of  the  first  kind.  A  pinch  bar  when 
we  pry  down  on  the  rail  and  against  the  tire  of  a  driving 
wheel  is  a  good  illustration  of  this  class  of  lever. 

A  lever  of  the  second  kind  has  the  power  F  applied  at 
one  end,  the  fulcrum  C  is  at  the  other  and  the  weight  or 
brake  beam  to  be  moved  is  between  them  at  W;  the  live 
lever  of  an  outside  hung  brake  is  usually  of  the  second 
kind.  If  you  use  the  pinch  bar  by  passing  it  under  the 
object  to  be  moved,  resting  one  end  on  the  ground  and 
lifting  up  on  the  other  it  will  show  you  the  second 
kind. 

With  a  lever  of  the  second  kind  the  weight  W  takes  as 
much  strain  as  both  the  power  F  and  fulcrum  C.  A  lever 
of  the  third  kind  has  the  power  F  attached  between  the 
ends  W  and  C;  a  lever  of  this  class  takes  more  power  in 
proportion  to  the  weight  to  be  moved  than  either  of  the 
other  kinds.  With  any  class  of  lever  the  strains  at  the 
ends  added  together  equal  the  strain  in  the  middle.  So 
you  see  the  power  developed  by  any  one  of  three  kinds  of 
levers  of  the  same  length  depends  on  the  relative  positions 
of  the  power,  weight  and  fulcrum. 


156 


BRAKE    LEVERAGE 


When  you  make  measurements  and  calculations  of 
brake  power,  in  case  the  pins  or  brake  jaws  are  much  worn! 
set  the  brake  by  hand  and  measure  the  levers  carefully  as 
a  mistake  of  a  very  short  distance  on  the  short  end  of  a  live 
lever  will  alter  the  power  considerable.  Always  multiply 
the  power  or  force  in  pounds  by  the  distance  in  inches 
from  the  point  F  where  power  is  attached  to  the  fulcrum 
•C  and  divide  this  product  by  the  distance  in  inches  from 
fulcrum  C  to  brake  beam  W. 


—  FORMULA  — 


LEVER  or  2ND  KIND        LEVER  or  3no  KINO 


On  page  154  is  a  small  cut  of  the  arrangement  of  levers 
for  a  coach  brake  with  the  Hodge  system  which  we  will 
use  to  illustrate  this  explanation. 

Beginning  at  the  brake  cylinder  where  the  power  is 
first  exerted,  the  pressure  at  F  where  the  piston  is  attached 
to  live  cylinder  lever  is  4,700  pounds  for  a  lo-inch  cylinder 
with  quick  action  triple.  This  lever  being  of  the  first  kind 
with  fulcrum  C  between  the  ends,  we  multiply  the  power 
4,700  by  12,  the  distance  to  the  fulcrum  C,  and  divide  this 


CALCULATING   BRAKE   LEVERAGE  157 


product  by  u^,  the  distance  from  the  fulcrum  to  W,  the 
Hodge  lever  rod  connection,  and  have  4,900  pounds  strain  ' 
on  this  rod  which  goes  to  the  Hodge  lever  at  X.  This  is 
a  lever  of  the  third  class  and  being  equally  divided,  each 
end  gets  half  this  power  or  2,450  pounds,  which  is  the  force 
at  the  top  end  of  the  live  truck  lever.  We  next  multiply 
2,450  by  the  distance  on  this  lever  from  F  to  C,  36  inches, 
and  divide  this  product  by  8,  the  distance  from  C  to  W,  and  ,'.; 
we  have  11,000  pounds,  the  strain  on  the  brake  beam.  A 
shorter  way  is  to  multiply  the  pull  at  top  end  of  live  lever 
2,450  pounds  by  4^2  the  proportion  of  the  live  lever.  To 
get  the  proportions  of  a  live  lever,  divide  the  total  length 
between  the  centers  of  outside  pin  holes  at  F  and  C  by  the 
distance  from  C  to  W  —  called  the  short  end  —  in  this  case  8 
into  36  or  4^  to  i.  If  the  force  at  F  is  2,450  pounds  and 
the  strain  at  W  is  11,000  pounds;  the  resistance  at  C  will 
be  8,550  pounds,  as  the  sum  of  the  strains  at  both  ends  of 
a  lever  must  balance  the  strain  in  the  middle.  This  strain 
of  8,550  pounds  on  the  bottom  rod  goes  to  the  bottom  end 
of  the  dead  truck  lever  at  F  and  is  to  be  multiplied  by  the 
distance  from  F  to  C  —  the  outside  length  of  dead  lever  — 
and  the  product  divided  by  the  distance  from  C  at  the  top 
end  of  dead  lever  to  W  the  brake  beam  connection;  if  the 
dead  lever  is  the  same  proportion  as  the  live  one  the  result 
will  be  11,000  pounds. 

Now  going  back  to  the  cylinder  levers,  the  tie  rod  has 
a  strain  of  9,600  pounds  which  is  the  sum  of  4,700  and 
4,900,  the  strains  on  both  ends  of  the  live  cylinder  lever. 
This  strain  goes  to  the  point  F  in  the  floating  cylinder 
lever  which  is  shown  fulcrumed  at  C  on  the  cylinder  head 
and  its  free  end  W  connected  to  the  Hodge  rod  for  the 
floating  lever  at  the  other  end  of  the  car  and  from  there 
the  power  goes  to  the  live  and  dead  truck  levers  of  the 
other  truck  as  already  explained. 

By  this  arrangement  of  levers  we  get  a  braking  power 
on  each  end  of  the  car  equal  on  both  trucks,  with  a  total 
amounting  to  twice  what  the  brake  piston  has;  but  we  get 
it  because  the  piston  travels  twice  as  far  as  it  would  if  the 


158  CALCULATING    BRAKE    LEVERAGE 

fulcrum  C  in  the  live  cylinder  lever  was  fixed  stationary; 
both  cylinder  levers  move  and  the  piston  travels  far 
enough  for  the  two. 

Both  cylinder  levers  need  not  be  of  the  same  length, 
but  they  must  be  of  the  same  proportion  if  the  same  strain 
is  to  go  to  each  end  of  the  car.  Coaches  have  cylinder 
levers  exactly  alike  for  each  end  of  the  coach ;  freight  cars 
do  not,  although  they  are  the  same  proportion. 

In  making  calculations  for  braking  power  for  coach 
equipment,  take  90  per  cent,  of  the  weight  which  the  wheels 
having  brake  shoes  attached  put  on  the  rail  under  them. 
With  all  wheels  braked  this  means  90  per  cent,  of  the 
weight  of  the  coach  when  empty,  a  twelve  wheel  coach 
with  only  eight  wheels  braked  takes  8/12  of  the  weight  as  a 
basis  for  calculation.  Use  70  per  cent,  of  the  light  weight 
of  any  freight  car  used  in  interchange  service;  while  100 
per  cent,  of  the  light  weight  of  a  tender  is  generally  used, 
a  tender  usually  has  a  supply  of  water,  fuel  and  tools  which 
hold  its  weight  up  above  the  skidding  point.  The  light 
weight  of  cars  and  coaches  is  used  when  making  leverage 
calculations  to  keep  the  brake  power  below  the  limit  at 
which  the  wheels  will  slide  when  the  brake  is  operated  on 
an  empty  car.  If  the  brake  cylinder  receives  its  supply  of 
air  from  the  auxiliary  only,  as  is  the  case  with  the  plain 
triple  valve  and  some  of  makes  of  quick-action  triples,  use 
fifty  pounds  as  the  equalized  piston  and  auxiliary  pressure. 
If  part  of  the  supply  comes  from  the  train  pipe,  as  is  the 
case  with  the  Westinghouse  quick-action  triple,  use  sixty 
pounds. 

Driver  brake  leverage  is  75  per  cent,  of  the  weight  at 
the  rail ;  an  engine-truck  brake  should  have  less  than  that, 
as  there  is  no  way  to  get  sand  to  the  rails  for  the  truck 
wheels  on  slippery  track. 


,      CAM  DRIVER  BRAKE  LEVERAGE. 

The  limited  space  in  this  book  will  not  allow  a  full 
description  of  how  the  cams  and  levers  are  designed,  but 
some  information  on  calculating  their  brake  power  will 
come  handy  to  the  men  operating  them.  The  illustration 
of  the  cam  brake  shows  its  various  parts. 


CffM  SC/X.W  Pitt 


FORMULA. 


These  cams  are  really  segments  of  wheels  with  x-x  for 
the  centers.  If  they  are  properly  laid  out  no  matter  how 
far  they  roll  down,  the  point  of  contact  at  the  edges  of  the 
wheels  will  always  be  on  the  line  between  the  centers  x-x. 

The  cam  as  used  with  the  brake  is  a  bell  crank  with  the 
long  arm  from  g  to  x  and  the  short  arm  from  x  to  a. 
A  true  bell  crank  requires  a  fixed  fulcrum  at  x  to  act  as  a 
brace  to  transmit  the  power  at  g  to  a,  but  in  the  case  of 


160  CALCULATING    DRIVER    BRAKE    LEVERAGE 

the  cams  no  fulcrum  is  needed  there,  for  the  faces  of  the 
cams  rolling  against  each  other  act  as  fulcrums. 

To  calculate  the  brake  power,  set  the  brake  full  on  and 
measure  the  distance  between  the  cam  link  pins  at  a-a. 
Also  measure  the  distance  between  the  cam  link  pins  g-g 
and  subtract  this  distance  from  the  distance  a-a;  one-half 
of  this  remainder  will  be  the  long  arm  of  the  bell  crank 
included  in  the  design  of  each  cam,  which  distance  we  will 
call  X  in  the  formula.  We  do  not  measure  clear  to  the 
face  of  the  cam,  because  the  power  is  applied  at  g-g, 
one-half  of  the  power  exerted  by  the  piston  going  to 
each  cam. 

As  the  cams  roll  down  against  each  other  when  the 
brake  is  set  their  faces  touch  at  one  point  only,  which  we 
will  call  the  point  of  "  rolling  contact."  Place  a  straight 
edge  from  one  of  the  cam  screw  pins  at  a  to  the  other,  on  a 
line  writh  their  centers  and  measure  from  the  straight  edge 
up  to  the  point  of  rolling  contact;  this  distance  is  the 
other  arm  of  the  bell  crank,  it  is  called  the  "offset,"  and 
is  the  distance  from  a  to  x  also;  this  is  named  O  in  the 
formula.  This  last  distance  divided  into  the  length  of  the 
line  from  b  to  a — the  long  arm  of  the  bell  crank — gives  the 
leverage  of  the  cam. 

Multiply  this  leverage  by  1,250  for  an  8-inch  cylinder 
or  by  2,000  for  a  lo-inch  cylinder,  which  will  give  the 
power  delivered  at  the  bottom  end  of  the  lever  at  a.  Mul- 
tiply this  power  by  the  whole  length  of  the  lever  from  a  to 
k,  called  Z  in  the  formula,  and  divide  the  product  by  the 
distance  from  the  pin  k  to  the  pin  i  in  the  brake  shoe 
head,  which  is  distance  Y;  this  quotient  is  the  brake  power 
delivered  at  that  shoe;  four  times  the  power  for  one  shoe 
will  be  the  brake  power  for  all  shoes,  which  should  be  75 
per  cent,  of  the  weight  on  drivers.  In  all  these  calcula- 
tions we  use  fifty  pounds  as  the  air  pressure  per  inch  on 
the  brake  piston. 

To  calculate  the  other  way  take  75  per  cent,  of  the 
weight  on  the  rail  at  the  drivers,  one-fourth  of  that  will 
be  the  power  required  at  each  shoe.  Multiply  this  amount 


OPERATING   THE    CAM    BRAKE  l6l 

by  the  length  in  inches  of  the  lever  from  i  to  k  and  divide 
the  product  by  the  length  from  k  to  a;  this  last  amount 
will  be  the  power  required  at  a,  delivered  by  the  cam. 

Divide  this  by  1,250  for  an  8-inch  cylinder  or  by  2,000 
for  a  10-inch  cylinder,  the  quotient  will  be  the  "  leverage  " 
of  the  cam,  and  should  correspond  exactly  with  the  cam  in 
use.  To  get  the  leverage  of  the  cam  divide  the  length  at 
X  by  the  offset. 

The  cams  are  designed  to  give  the  full  brake  power  of 
75  per  cent,  of  the  weight  on  drivers  when  the  shoes  and 
tire  are  worn  down  to  their  limit.  The  brake  power  in- 
creases as  the  length  of  the  cam  X  is  increased  by  wear  of 
shoes  and  tires,  but  this  does  not  affect  the  "  offset "  O. 
Therefore,  with  thick  new  tire  and  new  shoes  you  will  not 
get  the  full  brake  power,  because  the  long  lever  of  the  bell 
crank  in  the  cam  is  not  the  full  length  as  laid  out  for  a 
thin  tire.  To  avoid  the  difficulty  of  having  too  much  lev- 
erage with  thin  tire  the  radius  of  the  face  of  the  cam  is 
struck  from  a  point  one  and  one-fourth  inches  further  out 
than  at  x.  A  thick  or  thin  shoe  does  not  change  the  power 
as  much  where  the  cams  are  long  with  long  wheel  base  as 
with  very  short  cams. 

If  you  find  that  with  a  short  piston  travel,  say  two 
inches,  the  cams  do  not  roll  down  so  that  their  faces  sep- 
arate at  the  lower  corners,  as  shown  in  the  illustration,  the 
cam  links  are  too  short.  It  is  not  unusual  to  find  these 
links  put  up  too  short,  and  this  defect  reduces  the  brake 
power  very  materially.  Changing  the  brake  heads  and 
putting  on  a  wide  one  in  the  place  of  a  narrow  head  also 
reduces  the  brake  power,  as  it  shortens  the  length  of  the 
cam.  A  thick  shoe  shortens  the  cam  in  the  same  way. 

In  any  brake  the  proportion  between  the  piston  travel 
and  the  brake  shoe  travel  is  the  leverage.  For  instance,  if 
the  piston  travel  is  four  inches  and  the  brake  shoes  travel 
one-half  inch,  the  proportion  is  eight  to  one,  so  the  power 
from  the  piston  is  multiplied  eight  times.  If  you  can  get 
the  exact  brake  shoe  travel  of  a  brake  and  divide  it  into 
the  piston  travel  you  can  easily  find  the  brake  power. 


CALCULATIONS  FOR  AIR  PRESSURES. 

To  calculate  at  what  final  pressure  two  separate  vol- 
umes of  air  at  different  pressures  will  equalize  when  con- 
nected so  air  will  flow  from  the  higher  to  the  lower  pres- 
sure, it  is  necessary  to  reduce  the  volumes  and  pressures 
to  one  standard  of  comparison. 

Suppose  that  a  reservoir  has  a  volume  of  1,620  cubic 
inches  with  a  gage  pressure  of  seventy  pounds  per  inch. 
If  that  same  air  was  expanded  to  one  pound  gage  pressure 
per  inch  it  would  occupy  seventy  times  as  much  space  or 
70  x  1,620  which  is  113,400  cubic  inches  at  one  pound  pres- 
sure. We  will  call  this  amount  cubic-inch-pounds,  all 
volumes  and  pressures  can  be  reduced  to  this  standard. 

A  gage  shows  the  pressure  above  the  atmospheric  line, 
but  "  absolute  "  pressure  begins  at  the  vacuum  line ;  to  get 
absolute  pressure  we  add  fifteen  pounds  to  the  pressure 
shown  on  the  gage,  before  the  calculations  are  made  and 
subtract  fifteen  pounds  from  the  result  to  get  back  to  the 
gage  pressure  again.  If  the  calculations  refer  to  volumes 
which  contain  air  at  or  above  the  atmospheric  pressure, 
this  fifteen  pounds  need  not  be  taken  into  account.  If  any 
question  of  piston  travel  is  connected  with  it,  the  fifteen 
pounds  must  be  considered. 

We  will  take  the  case  of  a  main  reservoir  of  16,000 
cubic  inches  at  ninety  pounds  and  an  empty  train  pipe  of 
twenty-five  cars  which  will  be  the  same  volume.  Multiply 
the  volume  of  main  reservoir  by  the  pressure  and  divide 
the  product  by  the  combined  volume  of  both  reservoir  and 
train  pipe.  16,000  x  90=1,440,000  cubic-inch-pounds,  this 
divided  by  32,000  gives  45,  the  gage  pressure  at  equaliza- 
tion. 

Suppose  this  train  pipe  instead  of  being  empty  has  forty 
pounds  gage  pressure  in  it,  and  the  main  reservoir  ninety, 
forty  pounds  in  the  train  pipe  will  be  640,000  cubic-inch- 
pounds,  this  added  to  the  amount  in  the  reservoir  and  the 
sum  divided  by  the  combined  volumes  will  give  sixty-five 
as  the  pressure  at  equalization. 


164  CALCULATIONS   FOR  AIR  PRESSURES 

A  retaining  valve  is  holding  15  pounds  in  the  brake 
cylinder.  After  charging  the  auxiliary  to  70  another  full 
application  is  made,  we  can  figure  the  equalizing  pressure 
as  follows:  450  cubic  inches  at  15  pounds  is  6,750  cubic- 
inch-pounds.  The  auxiliary  at  70  holds  113,400  cubic- 
inch-pounds,  the  total  amount  in  both  is  120,150  cubic- 
inch-pounds,  which  now  expands  into  the  total  volume  of 
1,620  plus  450  or  2,070  cubic  inches.  Divide  the  full  amount 
of  air  by  the  total  space  and  we  have  58  pounds.  We  do 
not  figure  from  the  vacuum  line  in  this  case. 

When  calculating  the  pressure  at  which  the  brake 
cylinder  and  auxiliary  will  equalize  when  the  piston  moves 
out,  remember  that  there  is  no  atmospheric  air  in  the  space 
left  by  the  piston  in  moving  out  and  this  space  must  be 
filled  with  air  from  the  vacuum  line  of  absolute  pressure, 
so  we  must  add  fifteen  pounds  to  the  gage  pressure  of 
seventy  pounds,  which  gives  eighty-five  pounds. 

The  auxiliary  holds  about  1,620  cubic  inches  at  eighty- 
five  pounds,  this  is  137,700  cubic-inch-pounds  absolute 
pressure.  The  volume  of  an  eight-inch  brake  cylinder  with 
eight  inches  travel,  including  the  clearance  and  piping 
from  the  triple,  is  close  to  450  cubic  inches;  the  combined 
volume  is  2,070  cubic  inches.  Divide  137,700  by  this  com- 
bined volume  and  subtract  fifteen  from  the  quotient,  you 
will  then  have  the  equalizing  pressure  about  51.5  pounds. 

To  find  how  much  of  the  brake  cylinder  air  at  60 
pounds  comes  from  the  train  pipe  with  an  emergency  ap- 
plication and  how  much  from  the  auxiliary,  proceed  as 
follows :  The  brake  cylinder  volume  of  450  cubic  inches  at 
75  pounds  absolute  pressure  is  33,750  cubic-inch-pounds. 
The  auxiliary  of  1,620  cubic  inches  loses  10  pounds,  from 
70  down  to  60;  this  is  16,200  cubic-inch-pounds  from  the 
auxiliary ;  this  subtracted  from  33,750  leaves  17,550  cubic 
pounds  to  come  from  the  train  pipe.  Divide  17,550  by  the 
volume  450  cubic  inches  we  have  39  pounds  absolute  pres- 
sure; subtracting  15  pounds  to  get  gauge  pressure  we  have 
24  pounds  as  the  part  the  train  pipe  supplies;  this  varies 
with  the  piston  travel  and  condition  of  strainers,  it  is 
usually  less  than  this. 


PRESSURE    WITH    PARTIAL    APPLICATION  165 

When  you  make  a  partial  application  of  the  brake  and 
want  to  know  what  brake  cylinder  pressure  will  result 
from  any  certain  reduction  in  the  auxiliary,  proceed  as 
follows :  Say  we  make  a  ten  pound  reduction.  If  the 
volume  of  the  auxiliary  is  1,620  cubic  inches,  at  ten  pounds 
per  inch  the  total  amount  passing  from  the  auxiliary  to 
the  brake  cylinder  would  be  16,200  cubic-inch-pounds.  In 
this  calculation  we  will  allow  for  the  air  contained  in  the 
clearance  space  of  the  cylinder,  the  auxiliary  tube 'between 
the.  triple  valve  and  cylinder,  and  the  triple  valve  itself, 
which  amounts  to  an  average  of  47.92  cubic  inches,  which 
contains  air  at  15  pounds  per  inch  or  close  to  718  cubic- 
inch-pounds.  This  added  to  the  amount  coming  in  from 
the  auxiliary  makes  16,918  cubic-inch-pounds,  and  it  will 
equalize  in  the  450  cubic  inches  total  volume  of  the  brake 
cylinder  and  clearance  at  38  pounds  absolute  pressure,  or 
23  pounds  gage  pressure.  You  can  calculate  for  any  given 
reduction  the  same  way  from  any  pressure;  just  as  long 
as  you  do  not  make  a  train  pipe  reduction  that  will  cause 
the  brake  cylinder  and  auxiliary  to  equalize,  or  when  you 
do  that  it  stops  the  auxiliary  reduction.  A  ten  pound 
reduction  from  90  gives  just  the  same  pressure  as  at  any 
lower  pressure  till  you  reach  the  equalizing  pressure,  which 
is  usually  below  50.  The  next  ten  pound  reduction  from 
the  auxiliary  into  this  cylinder  of  air  having  a  pressure  of 
23  pounds  will  show  a  greater  proportionate  raise  on  the 
gage,  for  the  first  reduction  had  to  fill  the  cylinder  from 
the  vacuum  line  up  to  gage  pressure — 15  pounds — the 
second  one  had  this  work  done  for  it,  and  therefore  made 
a  better  showing  on  the  gage. 

When  making  tests  the  gage  will  not  always  show 
these  exact  amounts,  as  the  leakage  groove  uses  consider- 
able air,  auxiliaries  are  not  all  the  size  specified,  the  clear- 
ance in  the  end  of  cylinder  varies,  and  the  expansion  of 
air  lowers  the  temperature,  which  alters  the  pressure. 

The  question  of  the  fall  of  temperature  is  not  taken 
into  consideration  in  these  calculations,  as  the  tempera- 
ture of  the  air  in  the  brake  equipment  on  a  car  is  very 
close  to  that  of  the  atmosphere  at  all  times. 


l66  SIZE    OF    RESERVOIRS 

To  get  the  area  of  the  piston,  multiply  the  diameter  by 
itself  and  that  product  by  .7854.  To  get  the  volume  of  the 
cylinder,  multiply  this  area  by  the  piston  travel  and  add 
the  clearance.  This  clearance  consists  of  the  space  be- 
tween the  piston  and  the  pressure  head,  usually  fys  of  an 
inch,  the  pipe  between  the  triple  and  the  cylinder  and  the 
space  in  the  triple  valve  that  is  filled  with  brake  cylinder 
air. 

Reservoirs  are  so  constructed  that  it  is  difficult  to  cal- 
culate their  exact  volume  from  their  outside  dimensions, 
this  can  be  obtained  exactly  by  weighing  them  while 
empty,  then  filling  full  of  water  and  weighing  again;  the 
difference  in  weight  will  be  the  amount  of  water  contained. 
A  pound  of  water  at  62  degrees  occupies  27.71  cubic 
inches ;  I  cubic  foot  weighs  62.355  pounds. 

A  cast  iron  auxiliary  for  an  8-inch  freight  brake  holds 
about  1,620  cubic  inches. 

10x24  in.  wrought  iron  auxiliary  1.510  cubic  in. 
12  x  33  in.  wrought  iron  auxiliary  3.030  cubic  in. 
14x33  in.  wrought  iron  auxiliary  4.120  cubic  in. 
16x33  in-  wrought  iron  auxiliary  5.322  cubic  in. 

The  equalizing  reservoir  from  590  to  621  cubic  inches, 
the  latter  pattern  10  x  14^  inches  long,  hold  800  cubic 
inches.  A  freight  car  has  about  640  cubic  inches  in  the 
train  pipe,  hose,  cross-over  pipe  and  triple  valve  to  the 
bottom  of  the  triple  piston — all  this  space  contains  train 
pipe  air. 

Main  reservoirs  vary  in  size  to  suit  their  location  on 
the  engine,  when  of  sufficient  volume  there  are  usually 
more  than  one,  having  the  air  from  the  pump  passing 
into  the  first  one,  from  there  to  the  next,  and  so  on  to  the 
brake  valve.  This  gives  the  air  a  chance  to  cool  down  to 
the  normal  temperature  of  the  atmosphere,  when  it  will 
deposit  all  its  moisture  as  water  in  the  main  reservoir.  If 
the  air  passes  through  the  brake  valve  without  cooling 
down  it  will  leave  some  of  the  water  in  the  train  pipe — see 
question  8 — and  give  trouble  in  the  operation  of  the  brake. 

Main  reservoirs  should  have  a  volume  of  at  least  20,000 
cubic  inches.  Freight  engines  should  have  1,000  cubic 


TEMPERATURE    OF    AIR   DURING    COMPRESSION  167 

inches  capacity  for  each  car  in  the  train.  An  engine  that 
can  handle  a  75-car  train  should  have  75,000  cubic  inches. 
Large  main  reservoir  capacity  is  necessary  to  promptly 
release  all  brakes  on  a  long  train  and  will  in  a  measure 
prevent  stuck  brakes  and  slid  flat  wheels  on  the  rear 
cars — see  question  9.  A  large  main  reservoir  also  tends 
to  save  a  pump,  as  it  can  run  at  a  slower  speed,  for  it 
can  run  continuously,  not  intermittently. 

When  air  at  a  temperature  of  60  degrees  is  compressed 
from  the  atmosphere  line  up  to  a  gage  pressure  of  70 
pounds  the  temperature  rises  to  about  400  degrees ;  with  a 
pressure  of  90  pounds  it  is  about  450  degrees,  at  105  pounds 
it  is  490  degrees.  As  this  heat  is  the  result  of  the  mechan- 
ical energy  of  the  steam  developed  through  the  air  pump, 
you  can  readily  see  that  it  takes  more  power  from  the  boiler 
to  reach  a  high  pressure  than  a  moderate  one.  Also  the  air 
piston  will  come  nearer  the  end  of  its  stroke  before  the  air 
is  compressed  to  105  than  at  90  pounds,  so  that  a  less 
amount  of  io5-pound  air  is  delivered  than  of  90.  As  the  air 
usually  cools  off  to  the  normal  temperature  before  it  passes 
into  the  brake  cylinder,  we  can  take  no  advantage  of  any 
expansion  of  air  by  the  heat  of  compression. 

The  heat  that  is  given  out  by  compression  is  taken  up 
when  the  air  is  allowed  to  expand.  When  air  expands 
through  any  opening  from  a  high  to  a  low  pressure  it 
takes  up  or  absorbs  neat  from  all  surrounding  bodies,  this 
accounts  for  its  being  so  cool  when  coming  out  of  the 
bleed  cock,  exhaust  port  of  a  triple  or  exhaust  pipe  of  an 
engine  run  by  compressed  air,  in  some  cases  it  will  form 
ice. 

When  studying  the  equalizing  processes  in  the  opera- 
tion of  compressed  air  equipment,  remember  that  it  is  air 
that  flows  from  one  part  of  the  equipment  to  another  and 
not  pressure.  Pressure  is  a  condition,  air  is  a  substance 
or  material.  When  air  flows  from  the  auxiliary  to  the 
cylinder  it  will  change  the  conditions  or  pressure  in  these 
places,  but  the  pressure  does  not  flow  either  way. 

It  will  take  away  much  of  the  mystery  of  equalization 
if  you  bear  these  facts  in  mind. 


THE  NEW  YORK  AIR  BRAKE. 

The  important  parts  of  the  New  York  Air  Brake  that 
differ  from  those  of  the  Westinghouse  Automatic  Brake, 
are  the  Duplex  Air  Pump ;  Governor ;  Engineer's  Valves ; 
Compensating  Valve ;  Quick  Action  Triple  Valve ;  Air 
Signal  Valve  and  Train  Pipe  Strainer.  The  Brake  Cylin- 
ders and  pistons  in  all  their  details;  Reservoirs,  both  main 
and  auxiliary ;  Pressure  Retaining  Valves ;  Reducing  Valve 
for  the  air  signal  system ;  Train  Pipe  with  Hose  Couplings, 
Angle  and  Cut-out  Cocks  and  Conductor's  Valves  are  the 
same  in  both  systems  of  equipment;  their  construction  and 
operation  have  already  been  described  in  this  book. 

As  freight  cars  in  interchange  service  are  moved  from 
one  railroad  to  another  when  of  the  same  guage,  there 
will  bejn  all  freight  trains  some  cars  equipped  with  the 
Westinghouse  and  others  with  the  New  York  brake.  The 
Master  Car  Builders'  specifications  require  that  all  brakes 
in  a  train  shall  be  so  constructed  that  the  different  kinds 
will  operate  in  unison,  so  as  to  control  the  speed  of  the 
train  without  shocks.  For  that  reason  the  general  rules 
for  the  handling  of  trains  are  the  same,  whichever  brake  is 
used.  There  are  several  differences  in  the  construction  of 
these  two  kinds  of  brake  equipment,  that  give  different 
results  when  they  are  operated;  these  points  will  be  ex- 
plained later  on. 


THE  DUPLEX  AIR  PUMP. 

This  pump  has  two  steam  cylinders,  I  and  2,  and  two 
air  cylinders,  3  and  4;  the  steam  valves,  5  and  6,  being 
operated  by  reversing  or  tappet  rods,  8-8.  These  tappet 
rods  are  operated  by  the  tappet  plates  20,  which  are  securely 
fastened  to  the  lower  side  of  each  steam  piston  by  bolts  55. 
The  steam  cylinders  each  receive  steam  from  the  boiler  and 
exhaust  to  the  atmosphere,  the  air  cylinders  each  re- 
ceive free  air  from  the  atmosphere;  but  the  air  in  cylin- 


NO.    2    DUPLEX    PUMP 


169 


17°  DUPLEX    AIR    PUMP 

der  4  when  compressed  passes  into  cylinder  3  and  from 
there  is  forced  into  the  main  reservoir.  Thus,  the  air 
cylinders  compound  the  air,  while  the  steam  cylinders  work 
simple.  Each  steam  cylinder  of  the  No.  2  pump  is  7 
inches  in  diameter  and  9  inches  stroke,  the  low  pressure 
air  cylinder  4  is  10  inches  in  diameter,  the  high  pressure 
air  cylinder  3  is  7  inches  in  diameter;  both  cylinders  have 
the  same  stroke  as  the  steam  cylinders,  9  inches.  The 
volume  of  air  cylinder  4  is  twice  that  of  cylinder  3. 

The  sectional  view  on  page  169  shows  the  pump  with 
all  parts  in  the  position  when  making  its  first  stroke  after 
turning  on  the  steam,  the  steam,  piston  21  and  air  piston 
32  which  are  connected  by  the  piston  rod  18,  having  made 
a  little  over  half  their  up  stroke. 

Live  steam  comes  from  the  boiler  through  the  steam 
pipe  and  governor  and  into  the  steam  head  19  and  passes 
into  each  steam  chest  around  the  steam  valves  5  and  6. 
This  steam  passage  is  shown  by  dotted  lines  from  56  on 
each  side  of  the  number  19.  A  drain  cock,  54,  is  tapped 
into  this  passage  to  allow  the  condensed  water  to  be  blown 
out  when  first  starting  up  the  pump,  at  all  other  times 
while  the  pump  is  running  it  should  be  closed.  The 
exhaust  passage  is  shown  leading  from  the  exhaust  cavi- 
ties of  the  slide  valves  5  and  6  through  58.  Under  58 
comes  the  drain  cock  for  the  exhaust;  unless  the  pump 
sets  high  enough  so  all  condensed  water  will  drain  to  the 
smoke  arch  end,  this  cock  can  be  left  open  if  so  desired, 
providing  there  is  a  drip  pipe  leading  to  the  ash  pan.  The 
steam  head  is  made  with  right  and  left  side  connections  for 
live  and  exhaust  steam,  the  openings  not  used  are  closed 
with  threaded  plugs. 

When  steam  is  shut  off  from  the  pump,  there  being  no 
pressure  on  the  back  of  the  valves  5  and  6,  they  drop  to 
their  lowest  position  as  shown.  Live  steam  when  first 
turned  on  passes  up  through  port  23-24  into  cylinder  I, 
and  if  piston  22  is  not  already  at  the  bottom  of  its  cylinder 
i,  it  is  forced  down  and  held  there.  At  the  same  time  live 
steam  passes  through  port  26  under  piston  21,  forcing  it 


DUPLEX   AIR  PUMP  171 

and  air  piston  32  upwards;  the  air  in  cylinder  4  above 
piston  32  raises  valve  n  and  passes  into  the  upper  end  of 
high  pressure  air  cylinder  3  above  piston  31.  At  the  same 
time  while  piston  32  is  moving  up,  free  air  from  outside 
raises  inlet  valve  10,  passing  into  the  lower  end  of  low- 
pressure  cylinder  4  and  filling  it  ready  for  compression  on 
the  down  stroke  of  its  piston.  Piston  21  then  remains  at 
the  top  of  its  stroke  till  the  other  steam  piston  makes  an 
up  stroke. 

When  steam  piston  21  approaches  the  top  limit  of  its 
stroke,  tappet  plate  20  catches  the  button  on  the  top  end  of 
the  reversing  or  tappet  rod  8,  drawing  this  rod  and  slide 
valve  6  up  so  that  port  27  is  uncovered  to  the  live  steam 
and  port  23-24-25  is  connected  to  the  exhaust.  With  live 
steam  passing  under  it  and  the  upper  side  connected  to  the 
exhaust,  piston  22  moves  upward,  carrying  air  piston  31 
with  it  and  forcing  the  air  in  upper  end  of  the  high-pres- 
sure cylinder  past  the  final  discharge  valve  13  into  the 
main  reservoir.  At  the  same  time,  air  from  the  atmosphere 
flows  in  past  valves  10  and  12,  filling  the  lower  end  of  the 
high-pressure  cylinder  3  with  free  air.  The  low-pressure 
air  cylinder  has  one  inlet  valve  for  each  end,  9  and  10;  the 
high-pressure  air  cylinder  has  to  draw  its  supply  of  free 
air  through  two  inlet  valves  at  each  end,  9  and  n  at  the 
top  end  and  10  and  12  at  the  bottom.  Valves  n  and  12  are 
the  discharge  valves  for  the  low-pressure  cylinder ;  13  and 
14  are  the  final  discharge  valves  from  the  high-pressure 
cylinder  to  the  main  reservoir. 

As  piston  22  nears  the  end  of  its  up  stroke,  the  tappet 
plate  moves  rod  8  up,  drawing  valve  5  upwards,  this  con- 
nects port  26  with  the  exhaust  so  that  the  steam  in  cylinder 
2  under  piston  21  will  pass  out;  port  28-29-30  is  opened 
and  live  steam  passes  in  above  piston  21,  forcing  it  down, 
bringing  air  piston  32  with  it  and  compressing  the  air  in 
the  lower  end  of  cylinder  4  past  valve  12  into  the  lower  end 
of  high-pressure  cylinder  3,  and  drawing  a  supply  of  free 
air  past  valve  9  into  the  upper  end  of  cylinder  4.  During 
this  downward  movement  of  piston  21,  piston  22  is  sta- 


172  NO.    6    DUPLEX    PUMP 

tionary  at  the  top  of  its  stroke.  As  piston  21  nears  the 
bottom  limit  of  its  stroke,  tappet  plate  20  strikes  the 
shoulder  on  rod  8,  moving  it  and  steam  valve  6  to  their 
lower  position;  this  opens  port  23-24  to  live  steam  and  27 
to  the  exhaust ;  steam  piston  22  then  is  forced  down,  bring- 
ing air  piston  31  with  it;  the  air  in  the  lower  end  of  cylin- 
der 3  is  forced  past  final  discharge  valve  14  to  the  main 
reservoir,  free  air  from  the  atmosphere,  passes  by  valves  9 
and  ii  and  fills  the  upper  end  of  cylinder  3.  This  com- 
pletes a  round  trip  of  both  steam  and  air  pistons. 

By  means  of  the  tappet  rod  each  steam  piston  moves 
the  slide  or  steam  valve  that  opens  and  closes  the  steam 
and  exhaust  ports  for  the  other  cylinder,  so  that  when  one 
steam  piston  completes  its  stroke  it  has  moved  the  steam 
valve  to  operate  the  other  steam  piston  and  then  remains 
at  the  end  of  its  stroke  while  the  other  piston  makes  one. 
This  ensures  that  the  air  pistons  make  a  full  stroke  and 
leave  no  clearance  space  at  the  ends  of  the  air  cylinders 
except  the  volume  of  the  passages  to  the  discharge  valves 
and  leaves  the  air  pistons  in  the  proper  position  so  the  air 
from  the  low-pressure  cylinder  can  pass  into  the  high- 
pressure  cylinder  ready  for  the  final  compression  to  the 
main  reservoir.  All  the  air  valves  have  a  lift  of  1/10  of  an 
inch.  Oil  cups  54  are  in  the  top  heads  of  each  air  cylinder. 

The  No.  6  Duplex  Pump  here  shown  has  the  steam  end 
constructed  in  much  the  same  manner  as  the  No.  2  Duplex 
Pump.  The  air  inlet  and  discharge  valves  are  placed  in 
another  manner,  the  No.  6  pump  has  a  separate  air  inlet 
for  each  cylinder  to  take  in  atmospheric  air,  their  location 
is  shown  in  the  cuts  of  the  top  end  of  the  pump  and  the 
sectional  view.  The  bore  and  stroke  of  each  cylinder  is 
shown  in  the  cuts  as  well  as  the  course  of  the  steam  and 
air  by  the  arrows,  during  the  first  up  stroke.  A  description 
of  the  No.  6  is  not  necessary  here,  as  with  the  description 
of  the  No.  2  pump  and  the  illustrations,  the  operation  of 
the  pump  can  be  readily  understood.  The  low-pressure 
cylinder  takes  in  air  from  the  atmosphere  at  each  stroke  of 
its  piston  32  and  delivers  the  compressed  air  to  the  high- 


NO.  6  DUPLEX  AIR  PUMP. 


ALL  AIR  VALVES 


174  DEFECTS   OF  THE    DUPLEX    PUMP 

pressure  cylinder  through  the  intermediate  valves  n  and 
12.  At  each  stroke  of  the  high-pressure  piston  31  it  takes 
in  a  supply  of  air  from  the  atmosphere  through  its  inlet 
valves  15  or  16  and  afterwards  receives  the  air  from  the 
low-pressure  cylinder  in  addition  to  the  free  air  taken  in. 
The  defects  of  this  pump  are  treated  in  the  same  manner 
as  those  of  the  No.  2.  Leaks  at  the  inlet  valves  are  more 
easily  located  with  the  No.  6  than  the  No.  2,  as  there  is  a 
separate  strainer  for  each  inlet  with  the  No.  6. 


DEFECTS  OF  THE  DUPLEX  PUMP. 

When  the  Duplex  pump  stops,  first  open  drain  cock  54, 
if  steam  blows  out  strong  the  governor  is  all  right.  If 
very  little  steam  passes  out,  examine  the  governor.  If  the 
button  breaks  off  tappet  rod  8,  or  tappet  plate  20  gets  worn 
badly  or  very  loose,  the  steam  piston  on  that  side  will 
make  its  up  stroke  but  the  slide  valve  will  not  be  raised  up 
to  open  and  close  the  steam  and  exhaust  ports  for  the  other 
cylinder.  If  the  tappet  rod  is  broken  on  the  high-pressure 
side,  both  air  pistons  will  stop  at  the  top  of  their  stroke ;  if 
the  tappet  rod  is  disabled  on  the  low-pressure  side,  piston 
21  can  move  to  the  top  of  its  stroke,  but  valve  6  will  not  be 
moved  up,  steam  will  hold  piston  22  and  air  piston  31  at 
the  bottom  of  their  strokes.  Taking  off  cap  nuts  15  will 
soon  locate  which  tappet  rod  is  at  fault.  To  locate  at 
which  end  of  the  stroke  the  air  piston  has  stopped,  remove 
the  oil  cups  from  the  top  of  air  cylinders  and  run  a  piece 
of  wire  down  to  the  piston.  If  the  nuts  74  work  loose  and 
strike  the  top  head  so  the  piston  can  not  make  a  full  stroke, 
the  steam  valve  on  that  side  will  not  be  moved  to  change 
the  course  of  steam  to  the  other  cylinder,  and  the  other 
piston  will  not  move.  This  defect  acts  like  a  button  broken 
off;  it  can  be  located  by  taking  top  head  47  off. 

Worn  air  piston  packing  rings  will  allow  the  pump  to 
run  very  fast  and  not  make  much  air;  it  will  run  hotter 
than  usual  and  pound  badly.  The  air  cushion  necessary  to 
keep  the  air  pistons  from  striking  the  heads  will  be  lost; 


DEFECTS   OF   THE    DUPLEX    PUMP  175 

this  will  cause  the  pound.  Leakage  of  air  around  the  high- 
pressure  piston  rod  will  waste  the  air  already  compressed, 
and  allow  the  piston  to  strike  the  lower  head;  it  will  also 
make  the  strokes  uneven.  To  locate  worn  air  piston  pack- 
ing rings,  run  the  pump  very  slowly  against  full  pressure 
in  the  main  reservoir.  If  the  rings  leak  considerable, 
compressed  air  will  get  past  the  piston  in  the  latter  part  of 
its  stroke;  this  will  reduce  to  nothing  the  amount  of  free 
air  drawn  in  at  the  inlet  valves.  To  locate  the  defective 
piston,  note  which  one  in  making  its  stroke  is  not  drawing 
in  air  properly.  This  is  not  a  very  good  test  for  the  high- 
pressure  piston,  as  it  may  be  drawing  part  of  its  supply 
from  the  low-pressure  cylinder,  which  has  been  expanded 
by  the  heat  of  the  cylinder.  If  the  pump  works  all  right 
at  a  low  air  pressure,  and  as  the  pressure  increases  the  low- 
pressure  cylinder  seems  to  be  doing  most  of  the  work, 
examine  the  high-pressure  side  to  see  why  it  is  not  doing 
its  share.  The  low-pressure  piston  ordinarily  works  against 
a  pressure  of  three  atmospheres — 30  pounds  gage  pressure, 
which  is  the  pressure  on  the  high-pressure  piston  at  the 
beginning  of  its  stroke  when  both  cylinders  have  filled  full 
of  free  air  from  the  atmosphere. 

If  an  inlet  or  receiving  valve  9  or  10  leaks,  the  air  will 
blow  out  past  it  as  piston  32  moves  towards  it.  Both  valves 
9-11  or  10-12,  will  have  to  leak  if  any  air  gets  back  to  the 
atmosphere  from  the  high-pressure  cylinder.  Open  the  oil 
cup  on  the  low-pressure  cylinder,  run  the  pump  slowly 
against  the  full  reservoir  pressure;  if  valve  n  leaks  when 
the  high-pressure  piston  is  moving  up  air  will  pass  valve 
ii  and  blow  out  of  the  oil  cup.  If  final  discharge  valve  13 
leaks  stop  the  pump,  opening  the  oil  cup  on  the  high- 
pressure  cylinder  will  show  it.  If  valve  14  leaks,  the 
piston,  if  not  at  the  top  of  cylinder  3,  will  move  up  there 
unless  the  air  can  blow  out  around  the  piston  rod.  Leaky 
air  inlet  valves  will  cause  the  pump  to  make  irregular 
strokes,  quick  towards  the  leaky  valve  and  slow  away  from 
them.  If  discharge  valves  leak,  the  piston  will  move 
slowly  towards  the  leaky  valve  and  quickly  away  from  it. 


176  THE    PUMP    GOVERNOR 

A  leak  by  the  gasket  48  will  show  like  a  leaky  air  valve; 
to  be  sure  which  it  is,  the  best  way  is  to  take  up  head  47 
and  examine  the  gasket  and  air  valves.  When  the  air  valves 
or  their  seats  have  worn  so  as  to  materially  increase  the 
lift  or  allow  them  to  leak,  it  is  best  to  put  in  new  valves 
and  seats  that  are  in  perfect  order.  When  new  valves  are 
placed  in  the  old  seats  or  the  old  valves  ground  in  to  a  fit, 
be  careful  that  the  lower  end  of  the  wings  of  the  valve  does 
not  strike  on  the  cages  or  the  stops  of  the  valves  under 
them. 

The  exhausts  from  the  pump  when  run  very  slowly 
against  standard  pressure,  will  usually  show  where  the  air 
leaks  are  located. 

Leaky  steam  piston  packing  rings  will  cause  an  inter- 
mittent blow.  Run  the  pump  slowly  against  full  air  pres- 
sure, open  the  drain  cock  in  the  exhaust  at  58;  you  can 
soon  locate  the  defect.  A  leaky  steam  slide  valve  will 
usually  give  a  steady  blow. 

Steam  escaping  at  the  piston  rod  packing  is  liable  to 
be  drawn  in  at  the  air  inlet  valves,  and  fill  the  equipment 
with  water;  this  is  very  dangerous  in  cold  weather. 


THE  PUMP  GOVERNOR. 

The  New  York  Air  Brake  Co.  make  three  styles  of 
governors:  the  Single,  Duplex  and  Triplex.  As  these 
only  vary  in  the  number  of  air  diaphram  bodies  attached 
to  a  single  steam  valve  body,  we  will  describe  the  Duplex 
governor,  which  is  the  one  most  generally  used.  Air  enters 
the  governor  at  e  from  the  train  pipe  to  one  diaphram  body 
and  from  the  main  reservoir  to  the  other  diaphram  body. 
At  /  is  a  strainer  to  prevent  dirt  or  grit  passing  from  e 
into  chamber  A.  Air  passes  into  the  chamber  A  under  the 
corrugated  diaphram  13,  which  is  held  down  on  its  seat  14 
by  a  regulating  spring  10,  acting  on  the  diaphram  button  12. 
When  the  air  pressure  under  the  diaphram  exceeds  the  re- 
sistance of  the  spring  10,  the  diaphram  is  raised  off  its  seat 
on  14,  this  allows  air  at  the  train  pipe  pressure  to  pass 
down  through  a  and  C  into  B  on  top  of  piston  4,  which  at 


PUMP    GOVERNOR 


177 


Duplex  Governor. 

PLATE  Q  8. 


once  moves  down,  also  moving  steam  valve  5  down  against 
its  seat  and  shutting  off  the  supply  of  steam  from  the 
boiler  to  the  pump.  A  small  hole  at  o  lets  a  little  steam 

pass  through  to  the 
pump  so  it  will  make  a 
stroke  at  intervals.  A 
vent  port  V  in  the  cylin- 
der I  over  piston  4  al- 
lows air  to  blow  ou  t 
steadily  while  the  air 
pressure  is  operating  the 
|  governor,  this  also  tends 
to  keep  the  pump  mov- 
ing. When  the  air  pres- 
sure drops  so  that  spring 
10  can  hold  diaphram  13 
on  its  seat,  the  air  es- 
capes from  chamber  B 
over  piston  4  through 
vent  V  \  valve  5  and  pis- 
ton 4  are  raised  by  the 
steam  pressure  and  the 
steam  again  passes  to  the 
pump.  When  valve  5  is 
at  the  top  of  its  travel  a 
steam  tight  seat  is  at  S, 
so  no  steam  can  work  up 
under  the  piston  4.  The 
dotted  lines  at  x  show  the  location  of  the  drip  opening 
in  the  side  of  the  cylinder  i,  which  allows  any  steam  that 
works  up  past  valve  5  or  air  that  comes  down  by  packing 
ring  24  to  escape  to  the  atmosphere.  When  valve  5  is 
partly  open,  steam  can  blow  out  at  the  drip  steadily  as  its 
stem  does  not  make  a  steam  tight  fit  in  the  guide  6.  The 
regulating  springs  over  the  air  diaphrams  are  adjusted  by 
the  small  adjusting  screw  8  and  fastened  by  the  jam  nut  9. 
The  later  pattern  of  governors  have  a  large  adjusting 
nut,  it  is  shown  in  the  Duplex  Controller. 

The  single  governor  is  usually  set  at  70  pounds,  as  it 


178  PUMP   GOVERNOR 

controls  the  train  pipe  pressure  and  is  piped  to  passage  E 
in  the  brake  valve  on  the  train  pipe  side  of  the  excess  pres- 
sure valve  97. 

The  Duplex  governor  has  the  low-pressure  air  dia- 
phram  chamber  connected  to  the  train  pipe  or  chamber  A 
of  the  brake  valve,  the  opening  into  E  of  the  brake  valve 
must  be  plugged,  and  main  reservoir  air  to  the  high-pres- 
sure side.  The  train  pipe  side  is  set  at  70  pounds  and  the 
main  reservoir  side  at  90.  With  this  arrangement,  if  the 
governor  diaphrams  are  not  set  for  the  proper  pressures, 
the  train  pipe  pressures  in  running  and  full  release  posi- 
tions will  not  be  right. 

With  the  Double  Pressure  system,  where  a  low  train 
pipe  pressure  is  carried  with  empty  cars  and  a  higher  one 
with  loaded  cars,  both  sides  of  the  duplex  governor  are 
piped  to  the  opening  E.  In  the  pipe  leading  to  the  low- 
pressure  side  of  the  governor  there  is  a  cut-out  cock,  when 
this  is  shut  the  higher  train  pipe  pressure  will  be  carried. 

With  the  Triplex  governor  one  air  diaphram  is  con- 
nected to  the  train  pipe  and  set  at  one  standard  pressure, 
the  second  diaphram  is  set  for  a  higher  train  pipe  pressure, 
and  the  third  diaphram  is  connected  to  the  main  reservoir 
air  and  set  at  the  pressure  desired  there.  There  is  a  cut- 
out cock  in  the  air  pipe  leading  to  the  lowest  train  pipe  dia- 
phram, which  can  be  closed  when  necessary  to  carry  a 
higher  train  pipe  pressure;  this  cuts  the  lowest  one  out  of 
service.  The  diaphram  13  gets  gummed  up  on  the  seat  of 
14  so  that  in  some  cases  air  leaks  by  it  and  the  governor 
piston  is  operated  before  the  proper  pressure  is  reached. 
Or  it  may  get  gummed  up  so  much  that  air  can  not  pass 
down  to  the  piston.  For  defects  common  to  governors, 
see  page  40. 

THE  1902  MODEL  BRAKE  VALVE. 

The  duty  of  the  brake  valve  is  to  control  the  passage  of 
air  from  the  main  reservoir  to  the  train  pipe ;  from  the  train 
pipe  to  the  atmosphere  or  stop  the  flow  of  air  through  it  in 
any  direction.  The  engineer's  brake  valve,  when  in  full 
release  position,  should  allow  the  main  reservoir  air  to 


Engineer's  Brake  Valve. 
1902  MODEL. 

,        TO  / 

GOVERNOR  J 


FACE  OF  SLIDE  VALVE 


107 


ISO  THE    1902    MODEL   BRAKE   VALVE 

flow  directly  to  the  train  pipe  through  large  ports  to  equal- 
ize these  pressures  quickly.  It  should  allow  the  air  to 
pass  through  smaller  openings  in  running  position  and 
maintain  a  higher  pressure  in  the  main  reservoir  after  the 
train  pipe  pressure  has  reached  a  standard  amount.  It 
should  have  a  moderate  opening  for  the  train  pipe  air  to 
pass  to  the  atmosphere  in  a  graduated  service  application, 
and  should  automatically  close  the  opening  when  the  train 
pipe  pressure  has  been  reduced  the  desired  amount  to 
operate  the  triples  with  a  graduated  application.  It  should 
also  have  a  large  and  direct  opening  to  the  atmosphere  to 
exhaust  the  train  pipe  air  quickly  in  an  emergency,  so  the 
triples  will  operate  quick  action. 

The  New  York  Brake  Valve  is  shown  in  section  on 
page  179.  The  brake  valve  body,  lOi-A,  contains  a  main 
slide  valve,  1 14- A,  which  is  moved  back  and  forth  over  the 
slide  valve  seat  by  the  slide  lever  118  and  links  116;  this 
lever  is  attached  to  lever  shaft  120,  and  moved  by  handle 
123.  Plugs  96  can  be  taken  out  to  oil  the  slide  valve  114. 
Main  reservoir  air  enters  the  body  of  the  valve,  passing  up 
into  chamber  B,  and  is  all  around  the  sides  and  on  top  of 
slide  valve  114- A.  It  also  passes  to  the  red  hand  of  the 
gage  and  to  the  high  pressure  side  of  the  duplex  governor. 
The  black  hand  gets  air  from  the  train  pipe  side  of  the 
brake  valve.  When  this  valve  is  in  full  release  position, 
main  reservoir  air  passes  directly  through  the  port  a  into 
chamber  A,  which  is  connected  with  the  train  pipe  directly, 
so  that  in  this  position  main  reservoir  air  can  equalize  with 
the  train  pipe;  if  the  duplex  gage  is  right  both  hands  will 
show  the  same  pressure.  When  the  handle  123  is  moved 
back  to  running  position,  port  a  is  covered  by  the  end  of 
the  slide  valve  so  no  air  can  pass  through  a;  main  reservoir 
air  must  then  pass  from  B  under  excess  pressure  valve  97, 
raise  it  against  the  stiffness  of  its  spring  90,  pass  through 
E  into  the  cavities  M-M  in  the  face  of  the  slide  valve  and 
through  a  into  A.  Train  pipe  pressure  is  also  holding  valve 
97  down  in  addition  to  the  stiffness  of  spring  90,  so  that 
with  main  reservoir  pressure  on  one  side  and  train  pipe 
pressure  on  the  other  side  of  97,  spring  90  is  able  to  main- 


THE  NEW  YORK  BRAKE  VALVE 


181 


tain  a  steady  difference  in  these  pressures,  at  whatever 
amount  the  main  reservoir  pressure  may  be.  This  differ- 
ence is  usually  20  pounds. 

Two  sectional  views  are  shown  on  page  181  giving  the 
position  of  the  excess  pressure  valve  97,  the  ports  from  B 
to  E,  and  showing  the  main  reservoir,  train  pipe  and  gage 
connections.  The  connection  to  the  supplementary  reser- 
voir and  port  H  is  shown  on  page  179. 

In  the  lower  part  of  the  valve  body,  loi-A,  is  a  piston, 
104- A,  moving  in  a  bushing;  this  piston  by  means  of  the 


GAGE 

RED  HAND 

MAIN 

RESERVOIR 
PRESSURE 

•o 

MAIN 
RESERVOIR 

graduating  valve  lever  112,  can  move  the  graduating  or 
cut-off  valve  no,  which  rests  against  the  lower  face  -of 
slide  valve  114- A,  and  in  its  normal  position  covers  the 
port  F  that  is  connected  by  a  passage  through  the  middle 
of  the  slide  valve  with  port  G,  which  in  service  position  is 
open  to  the  atmosphere  through  cavity  C.  When  the  slide 
valve  is  moved  to  the  first  notch  in  service  application 
position,  train  pipe  air  can  flow  from  A  through  o,  ports  I? 
and  G  into  C,  and  reduce  the  train  pipe  pressure.  Chamber 
D  on  the  other  side  of  the  piston  104- A  is  connected  witH 
the  supplementary  reservoir  155,  which  has  a  pressure  in  it 


102  OPERATION   OF  BRAKE  VALVE 

at  the  beginning  of  the  train  pipe  reduction  equal  to  that 
in  the  train  pipe.  As  the  train  pipe  pressure  is  reduced, 
the  air  in  chamber  D  and  155  expands,  and  moves  piston 
IO4-A  towards  the  reducing  train  pipe  pressure  in  A,  this 
in  turn  moves  cut-off  valve  no  back  and  closes  port  F, 
thus  cutting  off  the  flow  of  train  pipe  air  to  the  atmosphere, 
without  any  movement  of  the  handle  123  to  lap  position; 
this  is  expected  to  reduce  the  train  pipe  pressure  about  4 
pounds.  A  further  movement  of  handle  123  to  the  next 
service  notch  will  move  valve  114- A  so  that  port  F  will  be 
again  opened;  when  the  proper  reduction  has  been  made, 
cut-off  valve  will  again  close  port  F.  Successive  reductions 
can  be  made  by  moving  handle  123  to  the  next  service  notch 
till  the  last  one  is  reached,  when  the  train  pipe  pressure  will 
have  been  reduced  about  23  pounds,  and  the  brakes  applied 
in  full  service.  The  size  of  the  supplementary  reservoir  is 
such  that  when  the  air  in  it  expands  into  the  additional 
space  made  when  piston  IO4-A  moves  clear  forward,  the 
pressure  will  be  reduced  from  70  to  about  47  pounds,  or  a 
little  over  two-sevenths  of  the  original  pressure;  with  a 
higher  pressure  the  total  reduction  will  be  greater. 

To  reduce  the  train  pipe  pressure  suddenly  and  directly, 
123  is  moved  at  once  to  the  emergency  position ;  this  opens 
the  large  ports  J-J  to  A  so  that  train  pipe  air  passes  through 
two  passages ;  one  on  each  side  of  F-G  and  out  at  K  to  C. 
This  sudden  discharge  of  train  pipe  air  through  the  large 
openings  will  reduce  the  pressure  quickly  and  operate  the 
triples  quick  action.  After  any  application,  whether  service 
or  emergency,  the  brake  valve  should  be  placed  in  full  re- 
lease position  till  the  train  pipe  has  been  charged  its  full 
length,  and  all  triples  moved  to  release  position,  if  it  is 
desired  to  release  all  brakes  properly. 

If  piston  IO4-A  has  been  moved  forward  by  the  pressure 
in  chamber  D  at  the  time  of  a  reduction  of  train  pipe  pres- 
sure, it  must  be  moved  back  to  its  normal  position  when 
the  brakes  are  released  if  it  is  to  be  ready  to  move  cut-off 
valve  no  to  graduate  the  next  train  pipe  reduction.  To  do 
this  some  of  the  air  in  chamber  D  and  reservoir  155  must 
be  discharged  to  the  atmosphere.  This  is  done  through 


OPERATION  OF  BRAKE  VALVE  183 

port  and  passage  O,  which  passes  through  the  valve  cover 
H5-A,  as  shown  in  illustrations,  back  into  the  valve  body 
IOI-A  and  out  to  C  through  port  J  when  the  valve  is  in  full 
release,  or  through  cavity  P  in  the  slide  valve  when  in  run- 
ning or  lap  position.  Another  passage,  H,  connects 
chamber  D  at  all  times  with  reservoir  155,  so  that  when 
air  can  pass  out  of  chamber  D  through  O,  it  can  also  pass 
out  of  reservoir  155.  With  air  exhausting  from  chamber 
D  and  train  pipe  pressure  in  A,  piston  IO4-A  is  at  once 
moved  back  to  its  normal  position;  also  moving  cut-off 
valve  no.  In  the  end  of  piston  IO4-A  is  a  valve,  180,  that 
closes  port  O  when  the  piston  is  in  the  normal  position 
and  the  brake  valve  in  full  release,  running  position  or  lap, 
and  prevents  any  air  from  chamber  D  flowing  out  at  port 
O.  Air  from  the  train  pipe  can  flow  from  A  up  past  ball 
valve  184,  and  recharge  chamber  D  at  all  times  when  the 
pressure  is  less  in  D  than  in  A;  but  cannot  flow  back  into 
A  as  the  valve  184  prevents  this.  This  recharges  cham- 
ber D  and  reservoir  155  as  soon  as  piston  104- A  moves  to 
normal  position  and  seats  valve  180,  closing  passage  O. 
The  opening  past  ball  valve  184  and  through  the  piston 
into  chamber  D,  is  much  smaller  than  O,  so  chamber  D 
air  can  be  exhausted  through  O  faster  than  it  can  feed  in 
at  184,  this  ensures  the  movement  of  piston  to  its  normal 
position.  The  older  pattern  of  Vaughn-McKee  valve  does 
not  have  this  recharging  attachment,  and  in  all  cases  in 
releasing  brakes  the  valve  must  be  replaced  in  full  re- 
lease an  instant  to  discharge  the  air  from  chamber  D,  then 
moved  to  running  position  to  recharge  chamber  D,  in  order 
to  get  the  graduating  action  of  piston  104. 

As  the  supplementary  reservoir  is  supplied  with  air 
from  the  train  pipe,  while  this  reservoir  is  charging  after 
an  application  and  release  of  the  brake  on  a  lone  engine 
with  the  older  type  of  the  Vaughn-McKee  valve,  the  train 
pipe  pressure  will  be  reduced  at  the  instant  of  placing  the 
valve  on  running  position.  This  reduction  of  pressure  may 
apply  the  engine  brake;  as  soon  as  air  begins  to  pass  the 
excess  valve  the  brake  should  release. 

If  the  supplementary  reservoir  pipe  is  broken  or  leaking 


184  DEFECTS  OF  THE  BRAKE  VALVE 

so  a  blind  joint  must  be  made  at  the  valve,  there  will  be  so 
little  air  in  chamber  D  that  the  equalizing  piston  will  not 
move  valve  no  to  graduate  and  stop  the  flow  of  air  from 
train  pipe,  and  handle  123  must  be  moved  to  lap  position  to 
stop  the  discharge  of  train  pipe  air. 

As  this  valve  has  two  sets  of  exhaust  ports,  one  small 
for  the  service  application  and  a  large  port  for  the  emer- 
gency application,  the  work  of  reducing  trie  train  pipe  pres- 
sure is  very  easily  regulated. 


DEFECTS  OF  THE   BRAKE  VALVE. 

If  air  leaks  past  main  slide  valve  into  train  pipe,  it  will 
not  maintain  excess  pressure,  if  the  valve  is  in  service  or 
lap  position  during  an  application  of  the  brake  this  leak 
will  recharge  the  train  pipe  and  release  the  brake.  To  test 
for  this  leak,  place  the  valve  on  lap,  close  the  cut-off  cock 
and  start  the  pump;  any  leak  into  the  train  pipe  will  be 
shown  on  the  black  hand.  If  the  leak  is  only  shown  when 
the  valve  is  in  running  position,  the  excess  pressure  valve 
is  at  fault ;  it  usually  only  needs  cleaning.  While  doing  - 
this  do  not  scratch  either  the  valve  or  its  seat,  or  it  will 
surely  leak  after  cleaning.'  If  the  cut-off  valve  no  leaks, 
it  will  not  stop  the  flow  of  air  from  the  train  pipe  in  a 
service  application ;  you  can  hear  the  continuous  blow  at 
the  exhaust  opening.  This  blow  will  stop  if  you  move  the 
valve  back  to  lap.  If  the  cut  out  cock  is  closed,  the  black 
hand  will  drop  to  zero  unless  there  is  a  leak  into  the  train 
pipe  cavity  A.  A  leak  through  the  leather  gasket  under  the 
cap  U5-A  that  allows  main  reservoir  air  to  get  into  port  O, 
will  cause  a  blow  at  the  exhaust  in  any  position  between  lap 
and  full  release.  In  any  other  position  it  will  charge  cham- 
ber D  direct  from  the  main  reservoir.  The  openings  in  the 
gasket  at  O  should  be  the  exact  size  of  the  port  O. 

A  leak  from  the  supplementary  reservoir  or  its  connec- 
tions, if  to  the  atmosphere,  is  easily  detected,  and  should 
be  remedied  if  the  automatic  closing  of  the  cut-off  valve 
no  is  to  be  satisfactory.  This  leak  will  reduce  the  pres- 
sure in  the  reservoir  so  the  piston  104  will  not  move.  A 
leak  from  chamber  D  back  into  the  train  pipe  can  be  de- 


THE  STRAIGHT  AIR  BRAKE  VALVE 


tected  by  closing  the  cut  out  cock  under  the  brake  valve, 
placing  the  valve  in  emergency  for  an  instant  to  empty 
chamber  A  and  then  in  the  second  service  notch;  a  leak 
into  chamber  A  will  be  shown  on  the  black  hand.  This  leak 
may  be  past  the  leather  packing  ring  or  by  the  ball  valve. 

THE    NEW   YORK   AIR    BRAKE   CO. 


Fij.  I. 


Straight  Air  Engineer's  Valve,  / 
&  5 


TO  MAIN  RESERVOIR 
"'PIPE 

Before  making  this  test  be  sure  main  slide  valve  does  not 
leak  from  main  reservoir  into  train  pipe.  Lost  motion  be- 
tween handle  123  and  main  slide  valve  will  allow  the  slide 
valve  to  leave  the  ports  only  partially  open ;  this  will  affect 
the  release  of  the  brake  very  seriously.  This  affects  a  train 
pipe  reduction  when  made  in  the  first  graduating  notch. 


•      THE  STRAIGHT  AIR  BRAKE. 


The  Straight  Air  Brake  valve  shown  on  page  185,  Figs, 
i  and  2,  has  a  slide  valve  227,  which  is  moved  by  the  lever 
222  with  its  lever  shaft  224,  and  slide  valve  lever  232. 
When  in  release  position,  Fig.  2,  the  port  b,  leading  from 
the  brake  cylinder  pipe  is  connected  with  the  exhaust  e  by 
the  cavity  c  of  the  slide  valve.  To  apply  the  brake  the 
handle  222  is  moved  to  application  position.  This  moves 
valve  227  so  as  to  lap  or  cover  the  exhaust  port  e  and  un- 

Safety  Valve  F&  6. 

With  Release  Lever. 


Straight  Air  f|j|  Reducing  Valve. 

cover  port  b.  Main  reservoir  air,  which  has  been  reduced 
to  45  pounds  at  the  reducing  valve,  Fig.  3,  can  then  flow 
from  A  into  b  and  thence  to  the  double  check  valves  and 
brake  cylinders.  Gasket  121  prevents  leakage  of  air  along 
the  shaft  224.  The  reducing  valve  shown  in  Fig.  3  is  lo- 
cated between  the  main  reservoir  and  the  brake  valve. 
The  diaphram  complete  consists  of  the  stem  21,  the  washer 
23  and  the  rubber  diaphram  32.  It  is  held  down  against 
th'e  air  pressure  in  B  by  the  regulating  spring  and  its  stem 


B-2   BRAKE   VALVE  187 

19.  As  long  as  the  pressure  in  B  is  less  than  the  regulating 
spring  is  adjusted  for,  which  is  45  pounds,  the  feed  valve 
26  is  ,held  off  its  seat.  When  this  pressure  reaches  45 
pounds,  the  spring  should  allow  the  diaphram  to  raise  and 
allow  feed  valve  26  to  seat,  thus  shutting  off  the  flow  of 
air  from  A  into  B. 

The  safety  valve,  Fig.  6,  has  a  release  lever  to  raise 
the  valve  off  its  seat  to  lower  the  brake  cylinder  pressure 
when  necessary.  This  safety  valve  for  the  driver  brakes 
can  be  located  in  the  cab,  if  desired,  and  is  to  be  set  at  52 
pounds,  as  is  the  tender  brake  safety  valve. 

The  double  check  valve  used  is  shown  in  Fig.  4,  on 
page  89.  The  same  rules  apply  to  the  operation  of  this 
straight  air  brake  as  to  the  Westinghouse  equipment. 

The  62  Brake  Valve  is  designed  to  operate  the  auto- 
matic brake  on  train  and  engine  in  the  same  manner  the 
1902  modej  valve  does,  and  in  addition  apply  the  driver 
brake  with  straight  air,  this  does  away  with  a  separate 
straight  air  brake  valve.  It  also  operates  an  accelerator 
valve  that  passes  air  out  of  the  train  pipe  to  the  atmosphere 
during  a  service  application  on  a  long  train  and  thus  makes 
the  operation  of  the  triple  valves  more  positive  and  quicker. 
There  is  a  duplex  controller  that  regulates  the  supply  of 
main  reservoir  air  to  the  brake  valve  by  reducing  it  to  train 
pipe  pressure  before  it  reaches  the  brake  valve,  so  the 
pressure  in  the  main  reservoir  side  of  the  valve  will  not 
rise  above  the  standard  desired  in  the  train  pipe,  this  does 
away  with  the  excess  pressure  attachment  used  with  the 
1902  model.  The  arrangement  of  this  equipment  is  shown 
on  next  page. 

There  is  no  ball  check  valve  184  in  the  piston,  cham- 
ber D  being  charged  from  the  air  in  B  around  the  slide 
valve  through  a  small  port  W  in  the  valve  seat  leading  into 
passage  H  and  the  supplementary  reservoir.  Passage  O 
and  vent  valve  180  in  this  valve  serve  the  same  purpose  as 
in  the  1902  model ;  to  discharge  air  from  chamber  D  so 
that  train  pipe  pressure  can  return  piston  193  to  its  normal 
position ;  when  valve  180  closes  port  O. 


B-2   BRAKE   VALVE 


189 


A  sectional  view  of  the  B2  valve  is  shown,  also  a  plan 
of  the  face  of  the  slide  valve  and  its  seat.  The  chief  dif- 
erences  between  this  valve  and  the  1902  model  are  the 
ports  in  the  slide  valve  and  the  seat.  Two  ports,  E  and 
V,  in  the  seat  are  connected  by  a  cored  passage  shown  by 
dotted  lines  through  the  valve  body  and  located  above 


passage  H,  into  this  passage  the  pipe  leading  to  the 
brake  cylinders  is  attached.  When  the  slide  valve  is  clear 
ahead  in  full  release  it  uncovers  port  E  so  air  from  the 
top  of  the  valve  in  B  can  pass  through  the  reducing  valve 
set  at  40  pounds,  to  the  brake  cylinders,  this  applies  the 
engine  brake  straight  air.  Air  from  B  passes  by  the  end 
of  the  slide  valve  and  also  through  ports  M  in  the  slide 


IpO  OPERATION   OF  B-2   BRAKE   VALVE 

valve  into  the  train  pipe  as  fast  as  the  air  can  pass  the 
controller,  releases  the  train  brake  and  charges  the  train 
pipe  and  auxiliaries.  Port  T  in'  the  seat,  leading  to  the 
accelerator  reservoir  is  open  through  J  in  the  slide  valve 
and  exhaust  C  to  the  atmosphere  and  port  O  is  the  same 
as  explained  with  the  1902  model.  Port  W  is  open  and 
keeps  chamber  D  equalized  with  B.  In  this  position  the 
train  brake  is  released  and  the  driver  brake  set  straight 
air. 

In  running  position  the  slide  valve  is  moved  back  cover- 
ing port  E  so  no  more  air  passes  to  the  brake  cylinder  pipe, 
port  V  in  the  seat  registers  with  R  in  the  valve  so  brake 
cylinder  air  can  exhaust  through  R,  J  and  C,  this  releases 
the  driver  brake.  Air  can  pass  to  the  train  pipe  through 
the  large  ports  M  in  the  slide  valve  so  running  position 
releases  both  the  train  and  driver  brakes.  Ports  O  and  T 
are  still  open  to  J  and  the  atmosphere.  On  lap  all  ports  are 
blanked  except  port  O,  this  is  left  open  to  return  the  piston 
and  graduating  valve  to  normal  position,  if  a  service  re- 
duction has  been  made  so  the  valve  will  graduate  at  the 
next  reduction. 

In  the  graduating  positions,  ports  F  and  G  are  opened 
by  a  movement  of  the  slide  valve  and  port  F  closed  by  the 
graduating  valve  as  with  the  1902  model.  But  as  port  S 
in  the  valve  is  opened  at  the  same  time  with  port  F,  when 
air  is  flowing  from  F  into  G,  it  is  also  flowing  through 
S,  the  passage  X  and  into  the  opening  Ac  that  is  connected 
by  port  T  in  the  seat  and  Y  and  to  the  accelerator  reser- 
voir. As  soon  as  the  proper  train  pipe  reduction  for  that 
notch  is  made  valve  no  will  close  ports  S  and  F.  A 
movement  of  the  handle  to  the  next  notch  will  open  ports 
S  and  F  again  and  valve  no  will  close  them;  train  pipe 
air  flows  to  the  accelerator  valve  chamber  at  the  same  time 
it  flows  through  F  and  G  and  exhaust  C.  When  the  last 
graduating  position  is  reached  the  restricted  passage 
N  in  the  end  of  the  slide  valve  has  been  moved  over 
port  V  so  air  begins  to  flow  from  the  brake  valve  to  the 
brake  cylinder.  As  the  engine  triple  valve  has  been  send- 
ing air  to  the  cylinders  during  the  service  application  the 


THE   DUPLEX   CONTROLLER 


191 


supply  of  air  through  port  V  tends  to  maintain  the  pressure 
during  a  full  application.  The  action  of  the  valve  in  emer- 
gency is  exactly  like  that  of  the  1902  valve  before  described. 
The  reducing  valve  used  with  this  equipment  is  the  same 
one  described  in  connecttion  with  the  Straight  Air  Brake. 


DUPLEX    CONTROLLER. 

THE  DUPLEX  CONTROLLER. 

This  valve  is  located  between  the  main  reservoir  and 
the  brake  valve;  its  duty  is  to  reduce  the  main  reservoir 
pressure  to  that  required  in  the  train  pipe  before  reach- 
ing the  brake  valve.  There  are  two  forms  of  it  in  ser- 
vice, only  the  latest  form  of  it  is  here  illustrated.  In  its 
construction  it  is  like  the  duplex  pump  governor  except 
that  its  valve  has  a  leather  seat.  The  regulating  tops  can 


IQ2  THE   DUPLEX   CONTROLLER 

be  located  in  the  cab  and  connected  to  the  controller  body 
by  a  copper  pipe.  One  of  the  tops  is  adjusted  for  the 
ordinary  train  pipe  pressure,  the  other  for  the  higher 
pressure  used  with  the  High  Speed  Brake.  When 
one  side  is  cut  in  by  the  union  three  way  cock  the 
other  is  cut  out,  either  one  of  the  two  pressures  can 
be  carried  in  the  brake  valve  and  train  pipe.  The  de- 
scription of  the  duplex  pump  governor  and  its  opera- 
tion will  be  sufficient  to  show  how  the  controller  op- 
erates. Air  enters  at  the  opening  marked  MR,  if  the 
controller  valve  is  open  it  can  pass  through  and  out 
to  the  brake  valve  at  BV.  When  necessary  in  steep  grade 
work  to  have  full  main  reservoir  pressure  in  the  brake 
valve  the  controller  valve  can  be  held  open  by  screwing 
the  hand  wheel  up  the  full  travel  of  its  screw. 


THE  ACCELERATOR  VALVE. 

This  valve  is  intended  to  discharge  train  pipe  air  during 
a  service  reduction  in  addition  to  that  taken  out  by  the 
brake  valve.  It  has  a  divided  reservoir ;  one  side  for  the 
accelerator  valve  to  which  the  valve  is  bolted,  the  other 
is  the  supplementary  reservoir  for  the  brake  valve.  When 
air  from  the  brake  valve  during  a  service  reduction  passes 
through  ports  S  and  T  to  the  reservoir  it  also  comes 
tthrough  port  Q  over  piston  65.  With  a  short  train,  less 
than  ten  cars,  port  S  is  closed  by  the  graduating  valve  be- 
fore sufficient  air  has  passed  into  the  accelerator  chamber 
to  operate  its  valve.  With  a  train  of  over  ten  ears  the 
pressure  in  the  chamber  will  build  up  till  it  is  sufficient  to 
force  piston  65  and  with  it  stem  67  and  valve  74  down 
against  the  tension  of  spring  31  in  the  bottom  of  the  valve. 
In  valve  74  is  an  oblong  port  a  and  in  the  seat  a  A. 
shaped  port  b.  When  valve  74  is  moved  down  port  a  first 
opens  to  the  pointed  end  of  port  b,  and  train  pipe  air  com- 
ing in  at  the  opening  TP  begins  to  flow  out  of  b  slowly. 
As  the  valve  74  is  moved  farther  down  by  the  increasing 
pressure  of  the  air  above  piston  65,  ports  a  and  b  are 
opened  wider  till  their  full  opening  is  made;  this  gives  a 


THE    ACCELERATOR   VALVE 


193 


gradual  discharge  of  train  pipe  air  that  with  a  long  train 
begins  about  four  seconds  after  the  brake  valve  begins 
discharging  air.  It  requires  15  to  17  pounds  pressure  in 
the  chamber  to  operate  the  valve.  Through  piston  65  is  a 
small  port  S  through  which  air  that  comes  over  the  piston 
can  discharge  into  the  space  under  the  piston  and  then  to 
the  atmosphere  through  port  T;  air  flows  out  here  at  the 
same  time  it  comes  into  the  reservoir  and  prevents  any 
sudden  rise  of  pressure  in  the 
reservoir.  When  piston  65  moves 
down  it  uncovers  port  R  in  the 
bushing,  this  also  takes  air  out  of 
the  reservoir.  As  soon  as  the 
graduating  valve  laps  port  S  in 
the  brake  valve,  no  more  train 
pipe  air  will  flow  to  the  cham- 
ber; ports  S  and  R  in  the  accel- 
erator piston  will  then 
H  gradually  reduce  the  pres- 
tf024  sure  in  the  chamber  and 
allow  spring  31  to  move 
valve  74  and  piston  65  up, 
gradually  closing  ports  a 
and  b.  When  piston  65 
7?  closes  port  R  the  flow  of 
air  out  of  S  alone  is  so 
£•  much  slower  that  piston  65 
gives  a  very  slow  closure 
un.to  port  b.  The  gasket  70 
makes  a  tight  joint  on  its 
seat  around  stem  67  when 
the  valve  is  closed,  so  train 
pipe  air  cannot  escape 
around  the  stem. 


ACCELERATOR    VALVE. 


THE  HIGH  SPEED  CONTROLLER.      * 

The    high    speed    controller    connects    with    the    brake 
cylinder  pipe  at  BC  and  to  the  train  pipe  at  BP,  so  that 


194 


THE   HIGH    SPEED  CONTROLLER 


train  pipe  air  pressure  is  always  in  the  body  of  the  valve 
and  when  greater  than  brake  cylinder  pressure  will  hold 
piston  107  in  normal  position  as  shown,  leather  gaskets 
are  on  each  side  of  the  piston  to  make  the  joint  tight.  A 
moderately  large  opening  around  the  valve  108  allows  air 
from  the  cylinder  to  reach  the  safety  valve  freely  and 
rapidly  reduce  any  excess  of  pressure  above  that  the  safety 
valve  is  set  for,  this  takes  place  in  a  service  application. 

In  an  emergency  ap- 
plication the  train 
pipe  pressure  is  sud- 
denly reduced  below 
what  the  brake  cylin- 
der can  build  up  to, 
and  piston  107  will 
move  over  to  the 
right  with  the  leather 
gasket  resting  against 
the  seat  C.  This 
brings  the  small 
valve  108  under  pas- 
sage G  so  the  cylin- 
der air  blows  down 
gradually  in  this  po- 
sition till  the  limit 
HIGH  SPEED  CONTROLLER.  for  which  the  safety 

valve  is  adjusted  is  reached,  this  should  be  53  pounds. 
Ports  D  and  F  are  to  allow  cylinder  air  quick  access  to 
the  ends  of  the  valve  108  and  piston  107  so  they  will 
move  with  a  low  difference  of  pressures  on  piston  107. 


THE  QUICK  ACTION  TRIPLE  VALVE. 

The  Quick  Action  Triple  Valve  is  used  on  passenger 
and  freight  cars  and  some  passenger  tenders.  The  one 
shown  in  section  on  page  196  is  the  older  type  of  freight 
car  triple.  The  passenger  triple  valve  for  12,  14  and  16 
inch  brake  cylinders  has  the  graduating  valve  48  located 
on  top  of  slide  valve  38,  and  the  service  port  through  valve 
38  as  well  as  in  its  seat,  the  vent  valve  piston  has  the  port 
F  through  the  stem  129.  The  new  type  of  freight  triple 
also  has  the  vent  valve  piston  made  like  the  passenger 
triple.  These  triples  are  shown  on  page  201. 

As  some  of  the  moving  parts  are  at  right  angles  to 
each  other,  this  cut  does  not  show  them  as  clearly  as  the 
diagrammatic  views  on  page  198.  The  same  reference 
numbers  and  letters  are  used  in  both  illustrations.  Refer- 
ring to  page  196,  the  triple  valve  body  125  contains  the 
two  bushings  in  which  main  piston  128  and  the  valves  38 
and  48  move;  126  is  the  front  cap  which  contains  vent 
valve  71  and  its  spring  132;  it  also  holds  the  stem  of  129 
in  position.  The  vent  valve  seat  or  "  middle  sec- 
tion" 130  makes  the  cap  for  the  cylinder  of  the  triple 
piston  128.  127  is  the  side  cap  and  covers  the  quick  action 
valve  piston  137.  Main  piston  128  is  extended  so  that  it 
forms  a  cylinder  in  which  another  piston,  129,  is  fitted, 
the  stem  of  which  passes  through  130  and  is  held  from 
moving  to  the-  right  by  a  clip  or  piston  stop  142,  so  that 
when  piston  128  moves  to  release  position  vent  valve  pis- 
ton is  in  its  normal  position,  and  a  chamber,  G,  is  left 
between  the  two  pistons.  A  small  port  F  through  piston 
129  allows  train  pipe  air  to  pass  in  and  out  of  chamber  G. 
This  port  is  of  such  a  size  that  when  piston  128  moves 
slowly  to  the  left  in  a  service  application,  the  air  in  G  can 
pass  out  to  the  train  pipe  side  of  piston  129,  and  piston  129 
will  remain  stationary  with  regard  to  130  and  vent  valve 
71,  as  shown  in  service  position  on  page  198.  This  vent 


THE   QUICK   ACTION    TRIPLE  VALVE  IQ7 

valve  is  held  on  its  seat  by  the  pressure  of  the  train  pipe 
air  and  spring  132. 

In  a  graduated  service  application  when  the  train  pipe 
pressure  is  reduced  in  A  the  auxiliary  pressure  in  the 
auxiliary  side  moves  piston  128  towards  the  decreasing 
train  pipe  pressure,  first  closing  the  feed  port  B  and  mov- 
ing* graduating  valve  48  with  the  piston.  As  soon  as  the 
lost  motion  between  the  piston  shoulders  and  exhaust  valve 
38  is  taken  up  valve  38  moves  and  closes  the  exhaust  port 
so  no  brake  cylinder  air  can  escape  to  the  atmosphere. 
The  port  to  the  brake  cylinder  under  valve  48  is  next 
opened,  and  air  from  the  auxiliary  flows  to  the  cylinder, 
applying  the  brake.  When  the  flow  of  train  pipe  air  out 
of  the  brake  Valve  stops,  the  reduction  in  A  also  stops, 
and  as  valve  48  is  still  open  the  auxiliary  pressure  soon 
gets  lower  than  that  of  the  train  pipe  so  piston  128  is 
moved  to  the  right  and  closes  valve  48  but  does  not  move 
valve  38;  this  holds  the  brake  set.  Another  train  pipe  re- 
duction produces  the  same  movements  of  the  piston  and 
valves  and  so  on  till  the  train  pipe  reductions  make  the 
pressure  lower  than  that  of  the  auxiliary,  when  the  piston 
will  not  move  back  to  close  the  graduating  valve  48.  To 
release  the  brake  the  train  pipe  pressure  is  raised  higher 
than  the  auxiliary,  this  moves  piston  128  and  valves  38 
and  48  to  release  position,  covering  the  service  port  and 
opening  the  exhaust  port. 

The  triple  piston  128  makes  a  full  stroke  in  either 
service  or  emergency  application,  the  edge  of  cylinder  128 
striking  the  leather  gasket  133,  so  that  no  graduating 
spring  is  used  to  assist  in  stopping  the  triple  piston  in  the 
service  position,  and  the  piston  does  not  get  any  assistance 
from  a  graduating  spring  when  starting  from  emergency  or 
full  stroke  towards  release  position. 

If  the  reduction  in  train  pipe  pressure  is  made  so  sud- 
denly that  the  air  in  chamber  G  can  not  pass  through  port 
F  fast  enough  to  equalize  with  the  train  pipe  reduction,  the 
pressure  of  air  in  G  will  move  piston  129  over  at  the 
same  time  piston  128  moves.  The  stem  of  129  will  push 


EMERGENCY  OPERATION  1 99 

vent  valve  71  away  from  its  seat,  as  shown  on  page  198 
and  201,  emergency  application;  train  pipe  air  from  the 
chamber  around  valve  71  can  How  rapidly  into  passage  H, 
and  thence  against  the  quick  action  piston  137.  This  in  its 
turn  is  moved  to  the  right  by  the  pressure  of  train  pipe  air 
and  quick  action  valve  138  is  unseated,  opening  a  large 
passage  for  auxiliary  air  to  flow  through  K  into  L— L, 
forcing  check  valve  117  off  its  seat;  the  air  also  passes  into 
the  brake  cylinder  through  the  usual  opening  at  the  gradu- 
ating valve.  No  air  from  the  train  pipe  reaches  the  brake 
cylinder,  only  that  from  the  auxiliary,  but  the  auxiliary  air 
passes  through  such  large  ports  K  and  L  that  the  equaliza- 
tion between  the  auxiliary  and  cylinder  is  almost  instan- 
taneous after  valve  138  is  opened.  As  soon  as  these  pres- 
sures have  equalized,  check  valve  117  closes  and  prevents 
brake  cylinder  air  flowing  back  into  L  and  thence  around 
the  stem  of  piston  137  to  the  atmosphere.  In  the  mean- 
time air  in  chamber  G  has  equalized  through  port  F  so  that ' 
spring  132  can  push  vent  valve  71  and  piston  129  to  their 
normal  positions.  When  vent  valve  71  seats,  no  more  air 
flows  from  train  pipe  to  passage  H ;  air  escaping  from  ports 
M  and  J  at  once  reduces  the  pressure  on  piston  137,  which 
is  moved  to  the  left,  its  normal  position,  by  the  stiffness  of 
spring  140.  Valve  138  is  closed  and  no  more  air  can  pass 
from  the  auxiliary  into  L,  and  all  the  quick  action  parts 
of  the  triple  valve  are  returned  to  their  normal  positions. 
Piston  128  having  made  a  full  stroke,  valve  48  is  open  so 
that  auxiliary  air  can  pass  into  the  brake  cylinder  and 
keep  the  pressures  equalized.  With  70  pounds  auxiliary 
pressure  and  the  standard  piston  travel  the  equalization  is 
the  same  for  full  service  and  emergency  applications,  50 
pounds  per  inch. 

Venting  the  train  pipe  air  to  the  atmosphere  past  valve 
71  and  through  ports  M  and  J,  should  reduce  its  pressure 
below  that  in  the  auxiliary ;  this  will  hold  piston  128  in  ser- 
vice position. 

The  sudden  venting  of  train  pipe  air  to  the  atmosphere 
at  this  triple  makes  a  sudden  reduction  at  the  next  triple, 


2OO  TRIPLE    VALVE    OPERATIONS 

which  in  turn  operates  quick  action,  and  so  on  from  one 
triple  to  another  to  the  end  of  the  train;  this  is  called  the 
"serial"  action. 

If  there  are,  close  to  the  head  end  of  the  train,  several 
triple  valves  cut  out,  or  defective  triples  that  do  not  operate 
the  vent  valve  so  as  to  vent  enough  air  from  the  train  pipe, 
or  cars  with  train  pipe  only,  the  sudden  reduction  may  not 
extend  far  enough  to  affect  a  quick  action  triple  so  it  works 
quick  action  and  continues  the  sudden  serial  reduction. 
About  three  "  cut  out "  triples  next  the  engine  is  the  limit 
to  have  the  quick  action  "  jump  over."  At  the  rear  end  of 
the  train  the  quick  action  will  jump  more  than  three  cars, 
because  the  volume  of  train  pipe  air  behind  these  defective 
triples  is  less  than  when  they  are  near  to  the  head  end  of 
the  train. 

This  type  of  triple  valve  does  not  send  any  train  pipe 
air  to  the  brake  cylinder;  the  brake  cylinder  pressure  is 
the  same  with  either  a  full  service  or  an  emergency  appli- 
cation; so  that  the  same  increase  of  train  pipe  pressure  is 
required  to  move  the  triple  valve  to  release  position.  When 
train  pipe  pressure  is  restored  so  that  it  is  greater  than 
auxiliary  pressure,  or  the  auxiliary  pressure  has  leaked 
down,  or  been  bled  out,  train  pipe  air  passing  through  port 
F  into  chamber  G  moves  piston  128  and  valves  38  and!  48 
to  release  position;  this  closes  the  service  port,  opens  the 
exhaust  port  to  release  the  air  from  the  brake  cylinder, 
and  opens  feed  port  B  to  recharge  the  auxiliary. 

If  the  piston  128  is  in  lap  position,  the  volume  of  air 
in  chamber  G  is  so  small  that  in  an  emergency  reduction  of 
train  pipe  air,  the  pressures  can  equalize  through  port  F 
and  piston  129  will  rarely  move.  If  piston  128  is  in  service 
position,  it  is  at  the  end  of  its  travel  and  can  not  move  any 
further.  Therefore,  after  pistons  128  in  the  triples  have 
responded  to  a  service  reduction,  no  matter  how  light,  the 
quick  action  parts  of  these  triples  will  not  move  and  a  sud- 
den serial  action  of  these  triples  will  not  take  place; 
only  a  heavy  service  application.  If  the  general  rule  to 
allow  all  the  air  to  pass  out  of  the  train  pipe  at  the  brake 


IMPROVED    QUICK    ACTION    XR1PLB    VALVB. 

FOR  it  AND  14  INCH  PASSBNGBR  CYLINDERS., 

PLATE   R  24. 


202  TRIPLE    VALVE    OPERATIONS 

valve  or  conductor's  valve  in  cases  of  emergency  or  danger 
is  promptly  obeyed,  all  brakes  that  operate  will  be  applied 
with  the  greatest  power  and  in  the  shortest  time  possible 
under  the  conditions. 

The  passenger  car  triple  shown  at  the  top  of  page  201 
has  the  graduating  valve  48  on  top  of  the  exhaust  valve  38 
instead  of  at  the  end  as  shown  in  the  next  cut,  of  R-6. 
Valve  48  is  fitted  into  a  notch  in  the  piston  rod  so  that  it 
moves  with  the  piston  128,  having  its  seat  on  top  of  valve 
38.  When  the  triple  piston  makes  it's  first  movement  in  a 
graduated  application,  valve  48  uncovers  the  air  port 
through  valve  38  and  allows  auxiliary  air  to  pass  into  this 
port,  although  air  cannot  pass  into  the  brake  cylinder  till 
the  exhaust  valve  has  moved  far  enough  to  open  the  ports 
into  the  cylinder.  Then  when  the  triple  piston  moves  back 
to  lap  position,  valve  48  moves  across  the  top  of  38  and 
covers  the  air  port;  the  lost  motion  between  the  ends  of 
valve  38  and  the  shoulders  on  the  piston  rod  allows  the 
piston  and  valve  48  to  move  without  moving  38.  In  this 
triple  R-24,  the  passages  from  the  auxiliary  to  the  brake 
cylinder  through  the  quick  action  ports  of  the  triple  are 
much  larger  than  in  the  older  form,  so  that  auxiliary  and 
brake  cylinder  pressures  equalize  much  quicker. 

The  improved  freight  triple  valve,  R-6,  is  shown  in 
emergency  positions,  vent-valve  piston  is  moved  down  so 
that  the  opening  of  port  F  through  the  stem  is  inside  the 
bushing  of  the  center  piece  130.  This  covering  of  port  F 
chokes  and  retards  the  flow  of  air  out  of  chamber  G  so 
that  the  vent-valve  piston  can  not  return  to  its  normal  posi- 
tion so  quickly.  It  thus  holds  vent-valve  71  away  from  its 
seat  longer,  which  makes  a  heavier  reduction  in  train  pipe 
pressure.  In  all  the  later  triples  check  valve  117  and  quick 
action  valve  138  have  rubber  seats,  and  port  F  is  in  the  stem 
of  piston  129. 

This  later  style  of  port  F  operates  the  same  as  the  port 
through  the  piston,  in  each  style  the  air  from  G  can  pass 
to  the  train  pipe  the  full  size  of  port  F. 


DEFECTS  OF  QUICK  ACTION  TRIPLE  VALVE. 

If  vent  valve  71  leaks,  or  is  held  off  its  seat,  there  will 
be  a  blow  at  the  round  port  M,  and  sometimes  at  the  two 
square  ports  J ;  also,  the  brake  may  not  release  as  train  pipe 
pressure  can  not  be  raised  enough  to  move  triple  to  release 
position.  If  the  vent  valve  piston  stem  129  is  bent  or  the 
piston  sticks  in  the  cylinder  of  128,  valve  71  will  be  held 
open.  This  piston  stem  129  and  the  cylinder  of  128  are 
easily  damaged  by  improper  handling,  and  should  be  care- 
fully handled  when  taken  apart.  A  small  leak  at  valve  71 
will  show  at  the  round  hole  M.  If  there  is  a  blow  at  the 
square  ports  J  in  the  triple  shown  on  page  196,  and  not  at 
M,  or  at  N  in  the  triples  shown  on  page  201,  air  is  prob- 
ably coming  from  the  quick  action  valve  138  and  thence 
past  the  stem  of  137,  which  is  not  an  air  tight  fit  in  the  cast 
iron  body  of  the  triple.  If  the  air  passing  by  valve  138  can 
not  go  by  stem  137,  it  will,  when  the  triple  is  in  release 
position,  pass  check  117  and  out  the  exhaust  port  or  pres- 
sure retainer,  or  leakage  groove.  A  leaky  packing  ring  in 
piston  128  will  affect  the  prompt  movement  of  this  piston 
to  release  position,  as  the  air  can  leak  by  this  defective  ring 
and  equalize  the  auxiliary  with  the  train  pipe  without  mov- 
ing the  triple  piston.  A  leak  by  this  ring  will  not  affect  the 
quick  action  operation  of  piston  129.  If  either  of  these 
rings  are  fitted  too  tight,  this  particular  triple  piston  may 
not  move  when  the  others  do  in  the  initial  reduction  of  a 
service  application,  and  when  it  does  move  it  may  cause 
quick  action  at  this  triple  only.  If  the  packing  ring  in  pis- 
ton 129  leaks,  the  air  in  G  can  pass  out  by  this  ring  and  this 
triple  is  not  likely  to  go  into  quick  action. 

A  leak  under  the  seat  of  valve  38  will  allow  auxiliary 
air  to  blow  out  the  exhaust  steadily.  If  under  valve  48  in 
the  triple  shown  on  page  196,  it  will  blow  at  the  exhaust 
when  the  triple  is  in  release  position.  With  the  triple  shown 


2O4  DEFECTS  OF  QUICK   ACTION   TRIPLE 

on  page  201  it  will  leak  in  lap  position  only,  and  then  into 
the  brake  cylinder.  If  the  packing  ring  in  either  piston  128 
or  129  is  too  tightly  fitted  or  gritty,  the  triple  may  work 
slower  than  the  others,  and  get  quick  action  with  a  moder- 
ate service  reduction ;  this  will  vent  a  little  train  pipe  air  to 
the  atmosphere  at  that  triple,  but  will  not  cause  any  other 
New  York  triples  to  work  quick  action.  If  the  stem  129  is 
bent  or  cylinder  of  128  is  bent  or  damaged,  it  may  produce 
the  same  effect.  This  defective  triple  can  usually  be  located 
by  the  flash  of  air  from  ports  M  and  J  towards  the  ground 
which  will  blow  the  sand  or  dust.  This  brake  may  release 
at  once  if  the  pressure  in  the  train  pipe  is  not  reduced  at 
that  time  below  that  at  which  that  auxiliary  and  brake 
cylinder  equalizes. 

Sand  works  into  the  ports  M,  N  and  J  and  may  cause 
the  quick  action  piston  137  to  stick  after  a  quick  action  ap- 
plication ;  this  will  hold  valve  138  open  so  auxiliary  air  will 
leak  away. 

Leaks  by  the  gasket  between  the  triple  and  the  aux- 
iliary on  a  freight  brake,  or  the  triple  and  the  cylinder  head 
on  a  passenger  brake  allowing  auxiliary  air  to  pass  to  the 
cylinder,  will  give  a  steady  blow  at  the  exhaust  port  while 
the  triple  is  in  release  position. 

If  the  port  F  has  been  enlarged  or  the  packing  ring  in 
piston  129  is  a  poor  fit,  so  it  leaks,  this  triple  may  not  go 
into  quick  action  when  the  sudden  train  pipe  reduction  is 
made. 

The  Compensating  Valve  is  used  in  high  speed  service 
and  is  designed  to  reduce  gradually  the  high  brake  cylin- 
der pressure  in  an  emergency  application  with  no  pounds 
in  the  train  pipe  and  auxiliary  to  60  pounds,  when  the 
valve  will  close  and  allow  no  more  air  to  escape  through 
it  from  the  cylinder. 

It  consists  of  a  piston,  100,  that  moves  in  a  cylinder  or 
bushing  with  several  small  ports  in  its  side,  in  normal  posi- 
tion the  piston  covers  them  so  no  air  can  pass  out  the 
ports.  Below  this  piston  is  a  diaphram  and  plate  fastened 
to  the  piston  that  prevents  the  passage  of  air  either  way. 


THE    COMPENSATING    VALVE 


205 


The  piston  is  held  up  in  normal  position  by  a  stiff  spring 
n,  the  tension  of  the  spring  is  adjusted  by  the  nut  12,  a 
cap  nut  13  makes  an  air  tight  joint  at  the  bottom  of  the 
spring  box,  screwed  into  the  side  of  the  spring  box  is  a 
check  valve  85,  containing  a  valve  86  with  a  small  port  a 
drilled  through  it. 


THE  COMPENSATING  VALVE. 


The  brake  cylinder  is  connected  above  the  piston  at  A; 
a  connection  is  made  to  the  check  valve  case  85  from  the 


206  THE   COMPENSATING   VALVE 

passage  H  in  the  side  of  the  New  York  quick  action  triple 
valve.  At  any  application  of  the  brake  air  from  the  cylin- 
der comes  into  A  and  gives  its  pressure  to  the  piston,  if 
this  pressure  is  any  greater  than  the  resistance  of  spring 
II  piston  loo  will  move  down  and  uncover  the  air  ports  in 
the  side  of  the  bushing;  this  allows  cylinder  air  to  escape 
and  reduce  its  pressure  till  spring  n  has  power  to  force 
piston  loo  up  and  close  the  ports.  A  thin  leather  gasket 
on  top  of  piston  makes  a  tight  joint  against  a  shoulder  of 
the  bushing  so  no  air  can  leak  out  till  the  piston  moves 
down. 

When  an  emergency  action  of  the  brake  is  made,  train 
pipe  air  from  the  quick  action  triple  comes  through  a  pipe 
into  the  check  case  85,  forces  valve  86  off  its  seat  and 
equalizes  in  chamber  B  in  the  spring  box.  Spring  87  seats 
valve  86  so  the  air  in  B  is  confined  there,  but  can  gradu- 
ally flow  out  through,  the  small  port  a  in  the  check  valve. 
Its  pressure  comes  against  the  diaphram  under  the  piston 
and  is  added  to  the  strength  of  spring  n,  holding  pis- 
ton 100  up  against  a  stronger  pressure  of  the  cylinder 
air  than  the  spring  alone  could.  This  prevents  the  cylin- 
der air  from  blowing  out  at  this  valve  till  the  air  in  B  has 
had  time  to  escape  and  it  then  blows  down  slowly.  In 
this  manner  it  compensates  for  the  change  in  braking 
power  as  the  speed  of  the  train  reduces.  This  matter  of  a 
change  in  braking  power  with  a  change  of  speed  has  been 
discussed  in  the  chapter  on  the  High  Speed  Brake. 

The  port  where  the  cylinder  air  enters  the  valve  at  A 
is  restricted  so  the  air  can  not  flash  into  A  at  a  high  pres- 
sure, which  aids  in  graduating  the  flow  of  air  from  the 
cylinder  during  an  emergency  application  when  the  no 
pound  auxiliary  pressure  is  used. 

These  openings  are  of  different  sizes  for  different  sized 
brake  cylinders  to  make  the  small  ones  blow  down  at  the 
same  rate  of  time  with  the  large  ones. 


NEW  YORK  AIR  SIGNAL  VALVE. 

The  Air  Signal  Valve  shown  in  section  on  this  page  has 
two  chambers,  A  and  B,  in  the  upper  and  lower  parts  of  the 
valve,  separated  by  a  rubber  diaphram  12.  Air  from  the 
main  reservoir  reduced  in  pressure  at  the  reducing  valve  to 
40  pounds  enters  the  signal  valve  from  the  signal  pipe  and 
passes  into  chamber  A  through  the  small  opening  d  which 
serves  to  restrict  the  flow  of  air  into  and  out  of  chamber 
A.  From  A  air  passes  up  around  the  posts  9  which  are 
firmly  attached  to  the  diaphram  stem  7.  Air  also  passes 
through  the  opening  a  in  stem  7,  and  through  the  very 
small  hole  at  b  into  chamber  B.  The  lower  end  of  stem  7, 


SIGNAL  VALVE        1903  MODEL. 

when  in  its  normal  position,  makes  a  tight  joint  on  the  top 
of  post  4  around  the  plug  5,  so  that  all  air  has  to  pass 
through  b  when  charging  up  chamber  B.  After  the  signal 
equipment  is  charged  to  the  standard  pressure,  a  sudden 
reduction  of  pressure  in  the  signal  pipe  by  allowing  air  to 
escape  at  the  car  discharge  valve  will  also  reduce  the  pres- 


208 


OPERATION  OF  AIR  SIGNAL  VALVE 


sure  in  chamber  A.  The  air  in  B  cannot  equalize  through 
b  fast  enough ;  so  pressure  in  B  will  raise  diaphram  12,  also 
raising  disc  valve  10  off  its  seat  at  c\  air  then  passes  from 
A  to  the  whistle  through  e  and  gives  a  blast.  When  dia- 
phram  12  raises,  the  lower  end  of  stem  7  at  n  raises  off 
the  post  4,  air  from  chamber  B  can  then  pass  up  through  n 
past  plug  5,  which  is  taper  at  its  upper  end,  through  pas- 
sage a  in  stem  7  and  equalize  quickly  with  the  air  in  cham- 
ber A.  The  diaphram  at  once  drops  to  its  normal  position 
with  stem  7  resting  on  post  4,  seating  valve  10  so  no  more 
air  passes  into  the  whistle.  Air  then  feeds  into  A  and  B 
till  the  pressures  are  equalized  with  the  signal  pipe  when 
another  reduction  can  be  made  at  the  car  discharge  valve 
and  again  operate  the  signal  valve. 

The  older  type  of  New  York  Signal  Valve  is  con- 
structed like  the  1903  model,  except  that  the  opening  a  pass- 
ing through  diaphram  stem  7  is  very  small,  and  air  passes 
through  a  slowly  when  charging  up  B  and  out  of  chamber 
B  much  slower  when  the  pressure  in  A  is  reduced  and  dia- 
phram 12  rises ;  this  causes  diaphram  to  remain  up  and 


REDUCING  VALVE. 


^VTO  MAIN  RESERVOIR 


hold  valve  10  open  longer 
than  necessary.  The  disc 
valve  10  and  chamber  A 
are  the  same  in  both  types 
of  signal  valves ;  the  bot- 
tom .Jpart,  chamber  B  is 
much  larger  in  the  1903 
model  than  the  older  type, 
so  there  is  a  larger  volume 
of  air  in  chamber  B  of  the 
1903  valve. 

The  1903  model  charges 
up  chamber  B  slowly; 
when  diaphram  12  raises, 
air  equalizes  from  B  into 
A  very  quickly,  thus  giving 
a  quick  closing  o  f  disc 
valve  10. 


AIR   SIGNAL  209 

The  reducing  valve  used  with  the  New  York  signal 
apparatus  is  shown  in  section  on  this  page.  Diaphram 
plate  6  is  held  down  by  a  regulating  spring  9  when  there 
is  less  than  standard  pressure  in  A.  This  in  turn  holds 
supply  valve  5  off  its  seat  so  that  main  reservoir  air  enter- 
ing at  4  can  pass  into  A  and  through  b  into  the  signal  pipe, 
charging  it.  A  rubber  diaphram  7  makes  an  air  tight  par- 
tition between  the  air  in  A  and  the  outside  air.  The  small 
holes  'v  in  the  spring  cap  3  are  to  allow  any  air  that  may 
leak  past  7  to  escape  to  the  atmosphere.  When  the  pres- 
sure in  A  reaches  the  standard  amount,  usually  40  pounds, 
diaphram  7,  stem  6  and  nut  8  are  raised  by  the  air  pres- 
sure against  the  stiffness  of  spring  9.  This  allows  spring 
10  to  close  supply  valve  5  so  that  pressure  in  A  will  not 
raise  any  higher.  When  the  opening  of  a  car  discharge 
valve  or  a  leak  in  the  signal  pipe  or  its  connections  reduces 
the  air  pressure,  spring  9  forces  the  diaphram  down,  opens 
the  supply  valve ;  this  allows  main  reservoir  air  to  feed  into 
the  signal  pipe  again. 

The  object  of  a  reducing  valve  is  to  maintain  signal 
pipe  pressure  lower  than  that  used  in  the  operations  of  the 
brake,  so  that  operating  either  the  brake  or  signal  will  not 
interefere  with  the  work  of  the  other.  The  opening  past 
the  supply  valve  is  made  small  so  air  will  pass  into  the 
signal  pipe  slowly  in  order  that  a  sufficient  reduction  can 
be  made  at  the  car  discharge  valve  of  any  car  to  operate 
the  signal  valve.  This  could  not  be  done  if  the  reducing 
valve  supplied  air  as  fast  as  the  car  discharge  valve  took 
it  out.  See  pages  126  and  127. 


OPERATING  THE  EQUIPMENT. 

When  making  the  initial  or  first  service  reduction  in 
train  pipe  pressure,  to  apply  the  brakes  lightly  on  a  train 
having  both  kinds  of  triple  valves  in  operation,  no  change 
in  the  manner  or  amount  of  reduction  is  needed,  as  both 
Westinghouse  and  New  York  triples,  if  in  good  order,  will 
apply  their  brakes  alike.  The  initial  reduction  should  be 
from  5  to  7  pounds,  depending  on  the  number  of  air  brake 
cars  operated;  the  length  of  the  entire  train  and  the  speed 
at  which  it  is  running.  A  short  train  will  not  need  so 
heavy  an  initial  reduction  as  a  longer  train.  There  will  not 
be  so  many  triple  valve  feed  ports  to  pass  air  from  the 
auxiliaries  to  the  train  pipe,  which  tends  to  prevent  move- 
ment of  the  triple  piston,  and  the  volume  of  train  pipe  air 
is  less  in  a  short  train  than  in  a  long  one ;  so  the  reduction 
through  the  brake  valve  is  made  quicker,  which  moves  the 
triples  quicker.  This  in  turn  passes  air  into  the  brake 
cylinders  faster,  so  the  pistons  move  over  the  leakage 
grooves  with  less  loss  of  air  through  the  grooves. 

On  a  long  train  the  first  reduction  may  be  7  to  9  pounds 
without  giving  serious  shocks,  unless  the  speed  is  very  slow, 
in  which  case  it  is  best  to  make  a  lighter  reduction.  A  5 
pound  initial  reduction  will  give  a  cylinder  pressure  of  less 
than  5  pounds  on  an  8-inch  travel  piston  which  will  not 
give  any  shock  to  a  train.  If  the  train  is  moving  fast,  the 
initial  reduction  can  be  much  heavier;  especially  in  the 
case  of  a  passenger  train.  It  is  advisable  to  apply  the 
brakes  with  considerable  force  when  at  high  speed,  the  re- 
tarding force  of  the  shoes  on  the  wheels  is  less  in  propor- 
tion than  at  slow  speeds. 

With  freight  trains,  at  whatever  speed,  allow  the  slack 
to  even  up  after  shutting  off  steam  before  applying  the 
brake,  then  apply  it  lightly  in  the  case  of  slow  speeds  to 
bunch  the  train  evenly  and  follow  up  with  other  reductions 
as  may  be  necessary  to  control  the  train.  Always  wait  at 


OPERATING  THE  NEW  YORK  BRAKE  VALVE  211 

one  reduction  till  the  air  has  stopped  flowing  from  the 
train  pipe  exhaust  of  the  brake  valve  and  the  triples  have 
had  a  chance  to  act  and  the  slack  to  even  up  before  making 
another  reduction. 

When  operating  the  1902  model  New  York  brake  valve, 
move  the  handle  to  first  service  position  notch  with  a  short 
train,  and  the  air  will  at  once  begin  to  discharge  from  the 
train  pipe  through  an  opening  in  the  main  slide  valve,  as 
the  pressure  reduces,  the  cut-off  valve  will  close  the  open- 
ing, it  will  entirely  close  when  the  pressure  is  reduced  the 
proper  amount  for  that  notch;  it  is  not  necessary  to  returm 
the  handle  to  lap  position.  Succeeding  reductions  may  then 
be  made  by  moving  the  handle  to  the  next  service  notches 
and  allowing  the  valve  to  graduate  the  flow  of  train  pipe 
air  and  stop  its  discharge,  or  the  handle  can  be  stopped 
between  the  notches.  When  the  last  graduating  notch 
is  reached  it  is  expected  that  a  reduction  of  20  to  23 
pounds  will  have  been  made  in  the  train  pipe  pressure. 
With  a  long  train  it  may  be  necessary  to  go  to  the  second 
or  third  notch  in  order  to  get  a  proper  initial  reduction  on 
a  long  train.  If  quick  action  is  desired  at  the  triples,  move 
the  handle  to  the  emergency  position  for  the  first  reduction 
and  leave  it  there  till  the  train  has  stopped  or  the  necessity 
for  the  quick  stop  has  passed.  This  is  a  general  rule  for  all 
brake  valves  and  all  triples  in  cases  of  emergency  or  danger 
which  must  be  observed. 

With  the  older  type  of  New  York  brake  valve,  the 
Vaughn-McKee  valve,  in  order  to  have  the  valve  cut  off 
the  discharge  of  train  pipe  air  automatically  in  a  graduated 
application,  the  valve  must  have  been  placed  in  full  release 
position  long  enough  to  discharge  all  air  from  the  supple- 
mentary reservoir  to  allow  train  pipe  pressure  to  move  the 
equalizing  piston  and  the  cut-off  valve  to  their  normal  posi- 
tions. It  must  then  be  moved  to  running  position  to  re- 
charge the  supplementary  reservoir  from  the  train  pipe 
air  till  it  equalizes,  after  which  the  piston  would  operate 
the  cut-off  valve  in  a  graduated  application.  If  the  valve 
was  only  placed  on  running  position  to  release  brakes  and 


212  OPERATING  THE  NEW    YORK   BRAKE  VALVE 

moved  to  service  application,  the  cut-off  valve  might  be 
over  the  graduated  reduction  port  so  no  air  could  pass  out 
of  train  pipe  and  it  would  be  necessary  to  go  farther  back 
towards  the  emergency  notch  to  discharge  any  train  pipe 
air.  When  operating  the  brake  with  this  valve  be  sure  to 
go  to  full  release  when  releasing  brakes,  then  stop  on  run- 
ning position  an  instant  if  you  expect  the  piston  to  operate 
the  cut-off  valve  in  a  graduated  service  reduction.  The 
1902  model  brake  valve  will  graduate  the  flow  of  train 
pipe  air  in  a  service  application,  as  it  automatically  dis- 
charges and  recharges  the  supplementary  reservoir  when  at 
lap  position  or  towards  release.  As  the  only  proper  posi- 
tion for  the  brake  valve  at  the  moment  of  releasing  all 
brakes  on  any  kind  of  a  train  or  engine  is  full  release,  this 
precaution  can  be  observed. 

With  a  short  train  or  lone  engine  the  brake  valve  of 
whatever  type  can  be  moved  from  full  release  to  running 
position  in  a  few  seconds  and  thus  avoid  overcharging  the 
train  pipe  in  case  there  is  a  high  main  reservoir  pressure. 

With  a  long  train  pipe,  leave  the  valve  in  full  release 
about  a  half  second  for  each  car  or  until  the  black  and  red 
hands  of  the  gauge  have  equalized  at  less  than  the  standard 
train  pipe  pressure,  usually  70  pounds,  then  move  to  run- 
ning position  and  leave  it  there  till  the  next  application, 
unless  the  train  is  a  very  long  one,  when  it  is  not  unusual 
for  a  few  of  the  brakes  on  the  head  end  of  the  train  to 
apply  from  overcharged  auxiliaries,  the  head  ones  charging 
higher  than  those  on  the  rear  when  main  reservoir  air  is 
flowing  rapidly  into  the  train  pipe.  If  any  set  they  can  be 
kicked  off  by  going  to  full  release  for  an  instant.  The 
New  York  brake  valve  has  an  excess  valve  to  maintain  a 
difference  of  pressure  between  the  main  reservoir  and  train 
pipe  so  the  instructions  about  carrying  excess  pressure  with 
the  Westinghouse  D-8  brake  valve,  found  in  the  previous 
pages  of  this  book,  will  apply  to  the  New  York  brake  valve. 
Questions  20,  21  and  65  refer  to  this  matter.  Always  use 
full  release  position  to  release  brakes  with  any  valve,  and 
it  is  a  vital  point  in  quick  recharging  of  auxiliaries,  as  when 


RULES     FOR     RELEASING     BRAKES  213 

on  a  hill,  to  keep  the  valve  in  full  release  as  long  as  pos- 
sible. 

Many  railroads  have  imperative,  iron-clad  rules  about 
certain  air  brake  work  which  are  made  to  prevent  careless 
or  unskillful  air  brakemen  from  doing  considerable  damage. 
While  only  a  very  few  of  the  men  handling  the  brake  may 
be  in  the  class  mentioned,  yet  the  rule  must  be  observed  by 
the  skillful  as  well  as  the  careless  ones.  One  of  these  rules 
is :  "  Do  not  release  the  brakes  on  a  long  train  when  run- 
ning at  a  slow  speed,  but  come  to  a  full  stop  first.'*  This 
speed  is  usually  below  eight  miles  an  hour.  This  rule  is 
made  because  the  shocks  to  the  train  caused  by  the  slack 
running  in  or  out  of  the  train  quicker  than  all  the  brakes 
can  release,  is  usually  certain  to  break  the  train  in  two  or 
more  parts.  With  the  use  of  an  additional  engine  and  ten- 
der brake,  either  the  Straight  Air  or  the  E.  T.  brake ;  retain- 
ing valves  on  engine  and  tender  brakes  or  cocks  so  arranged 
as  to  hold  the  engine  and  tender  brakes  applied,  the  train 
brake  can  be  released  at  a  slow  speed  without  serious 
shocks.  Retainers  depend  on  tight  piston  packing  and 
tight  joints  for  their  value.  If  the  joints  or  packing 
leathers  leak,  retainers  are  useless  for  this  purpose.  This 
"  iron-clad  rule "  applies  as  well  to  long  passenger  trains, 
when  consisting  of  over  twelve  coaches,  a  release  at  slow 
speed  without  the  use  of  some  device  on  the  engine  to 
hold  the  slack  is  almost  certain  to  break  the  train  in  two 
parts.  The  size  of  the  main  reservoir  and  amount  of  excess 
pressure  have  considerable  to  do  with  the  ease  and  cer- 
tainty of  releasing  all  brakes  quickly  on  a  long  train, 
large  volume  and  high  excess  make  the  operation  sure  on  a 
long  train.  You  should  remember  that  there  is  more 
difference  in  the  reservoir  and  train  pipe  pressures  after 
a  2O-pound  reduction  than  after  a  5-pound  reduction.  This 
may  explain  the  reason  for  stuck  brakes  on  a  long  train 
after  a  light  application.  This  matter  is  treated  of  on 
pages  50  and  107.  One  prominent  railroad  handling  long 
trains  of  air  braked  ore  cars  allows  the  release  of  a  few 
brakes  at  a  time  when  running  at  a  slow  speed,  instead 


214  PARTIAL    RELEASE    OF    BRAKES 

of  coming  to  a  full  stop.  After  a  full  application  or  nearly 
so,  when  necessary  to  release  a  few  of  the  brakes  at  a 
time  and  allow  the  train  to  keep  moving  during  releasing, 
the  brake  valve  is  moved  from  lap  to  running  position  for 
an  instant  to  raise  the  train  pipe  pressure  a  very  little, 
not  over  a  pound,  when  a  few  brakes,  usually  those  near 
the  head  end  of  the  train  will  release.  The  next  time  the 
valve  is  placed  in  running  position  for  an  instant,  brakes 
will  release  in  various  parts  of  the  train ;  this  operation  can 
be  repeated  till  the  train  pipe  pressure  is  raised  about  five 
pounds  in  all.  Between  each  release  allow  the  slack  to 
even  up.  If  this  work  is  skillfully  done  and  the  triples  are 
in  good  order,  very  few  brakes  will  remain  applied  after 
the  5-pound  raise  in  pressure.  Then  with  good  stiff  excess 
go  to  full  release  and  quickly  charge  the  train  pipe  up  its 
entire  length  to  ensure  that  all  triples  are  moved  to  release 
position.  This  process  has  a  much  different  effect  on  a 
train  at  slow  speed  from  releasing  all  triples  with  the  same 
recharge  of  train  pipe.  It  also  operates  better  on  a  train 
of  ore  cars  which  are  either  all  loaded  or  all  empty,  than 
on  an  ordinary  freight  train  having  loads  and  empties 
mixed  up  in  the  train;  for  this  reason  it  takes  great  skill 
to  handle  a  freight  train  in  this  manner.  A  full  release  of 
all  triples  from  one  movement  of  the  brake  valve  at  slow 
speed,  usually  breaks  the  train  in  two;  for  that  reason  all 
roads  condemn  the  practice.  In  releasing  brakes  an  en- 
gineer should  know  the  grades  and  how  they  affect  the 
bunching  or  stretching  of  a  train. 

One  of  the  questions  usually  asked  in  an  air  brake  ex- 
amination is  "  trace  the  air  through  the  air  brake  system; 
tell  where  it  goes  and  how  it  operates  the  various  parts  of 
the  equipment."  Some  air  brake  instructors  ask  this  ques- 
tion at  the  beginning  of  their  examination.  As  a  complete 
answer  to  this  question  requires  a  good  knowledge  of  the 
entire  equipment,  in  this  book  it  is  left  tiJJ  the  last. 

With  the  Westinghouse  equipment  (see  general  ar- 
rangement of  brake,  facing  title  page),  air  from  the  atmos- 
phere, enters  at  the  inlet  or  receiving  valves  of  the  air 


TRACING   THE   FLOW    OF   AIR  21$ 

pump,  when  the  piston  moves  in  the  air  cylinder,  filling  the 
space  left  by  the  piston.  As  the  piston  makes  a  stroke  the 
air  in  the  cylinder  that  is  compressed  passes  by  the  dis- 
charge valves  into  the  main  reservoir  and  form  there  to 
the  brake  valve,  where  it  is  above  the  rotary  valve.  In 
full  release  position  it  passes  through  the  direct  supply 
port  in  rotary  into  the  pocket  in  the  rotary  seat,  around  the 
partition,  up  into  the  large  cavity  in  the  lower  side  of  the 
rotary,  then  into  the  train  pipe.  At  the  same  time  it  passes 
through  the  feed  port  in  the  rotary  and  the  preliminary 
exhaust  port  into  chamber  D  also  through  the  equalizing 
port  into  chamber  D;  main  reservoir  air  goes  to  red  hand 
of  the  duplex  gage  and  pump  governor  and  warning  port 
to  atmosphere.  From  chamber  D,  air  goes  to  the  black 
hand  of  gage. 

In  running  position  air  passes  through  the  running 
position  or  feed  port  into  the  feed  valve  and,  until  the  sup- 
ply valve  closes,  on  into  the  train  pipe.  In  this  position  air 
passes  from  the  train  pipe  up  into  the  cavity  in  the  rotary 
and  then  to  chamber  D  through  the  equalizing  port.  With 
the  D-8  or  1899  valve  in  running  position  air  passes 
through  feed  port  in  rotary  to  the  excess  valve;  by  the 
excess  valve  into  train  pipe.  With  D-8  valve  train  pipe 
air  goes  to  the  governor,  with  the  other  valves,  main  reser- 
voir air  operates  the  governor.  When  the  governor  oper- 
ates air  flows  past  the  diaphram  valve  in  over  the  air 
piston  and  some  air  passes  out  the  vent  port. 

The  air  in  chamber  D  flows  into  the  brake  valve  reser- 
voir with  all  types  of  brake  valve.  Train  pipe  air  flows 
back  until  it  reaches  an  angle  cock  or  stop  cock  that  is 
closed.  It  flows  into  every  triple  valve  that  is  cut  in  and 
connected  to  the  train  pipe,  pressing- against  the  bottom  or 
train  pipe  side  of  the  triple  piston.  When  this  piston  is  in 
release  position  air  flows  through  the  feed  groove  around 
the  triple  piston  into  the  auxiliary  reservoir  till  the  pres- 
sures are  equalized.  Air  also  passes  up  the  pipe  to  the 
conductor's  valve.  When  the  pressures  in  the  train  pipe 
and  auxiliary  have  equalized  at  70  pounds  the  brake  is 


2l6  TRACING   THE   FLOW    OF   AIR 

ready  for  an  application;  we  will  explain  a  service  appli- 
cation first. 

Moving  the  handle  of  the  rotary  to  service  position  first 
laps  the  port  that  admits  main  reservoir  air  to  the  train 
pipe,  closes  the  equalizing  port  between  chamber  D  and 
the  train  pipe  and  opens  the  preliminary  exhaust  port  so 
chamber  D  air  escapes  to  the  atmosphere.  This  reduces 
chamber  D  pressure  over  the  equalizing  piston  train  pipe 
pressure  then  raises  this  piston,  which  opens  the  train  pipe 
exhaust  valve  so  train  pipe  air  flows  to  the  atmosphere, 
reducing  the  pressure  at  each  triple  valve.  The  triple  pis- 
ton moves  towards  the  reducing  pressure,  closing  the  feed 
port,  moving  the  graduating  valve  to  open  its  port  in  the 
slide  valve,  the  slide  valve  moves  so  the  exhaust  port  is 
closed,  next  opening  the  air  port  to  the  brake  cylinder  so 
that  auxiliary  air  flows  into  the  brake  cylinder  and  pushes 
out  the  brake  piston  which  sets  the  brake. 

To  release  the  brake  the  brake  valve  is  placed  in  full 
release  position;  main  reservoir  air  passes  into  the  train 
pipe  as  already  described.  This  moves  the  triple  valves  to 
release  position,  closing  the  air  ports  to  the  brake  cylinder, 
opening  the  exhaust  port  so  the  air  can  flow  from  the  cyl- 
inder to  the  atmosphere  and  opening  the  the  feed  groove 
so  train  pipe  air  can  flow  into  the  auxiliary.  Air  also 
flows  into  chamber  D  and  brake  valve  reservoir. 

If  a  retaining  valve  is  used,  brake  cylinder  air,  after 
leaving  the  exhaust  port,  passes  through  a  pipe  to  the  re- 
tainer, when  this  valve  is  in  release  position  the  air  passes 
directly  out.  If  the  valve  is  in  retaining  position  air  pres- 
sure raises  the  valve  and  passes  up  into  the  case  of  the  re- 
tainer and  then  out  through  the  small  opening  in  the  case 
till  the  pressure  drops  to  15  pounds,  when  the  valve  seats 
and  holds  the  air  in  the  brake  cylinder  till  the  retainer  is 
turned  to  release  position. 

When  making  an  emergency  application  of  the  brake 
the  brake  valve  is  placed  in  emergency  position.  Train 
pipe  air  passes  out  very  rapidly  through  the  direct  exhaust 
port  at  the  same  time  chamber  D  air  passes  out  at  the 


TRACING   THE   FLOW   OF   AIR  217 

preliminary  exhaust  port  of  the  1892  brake  valve.  Air 
passes  out  of  the  train  pipe  so  rapidly  that  the  triple  valve 
cannot  reduce  auxiliary  pressure  as  shown  in  service  ap- 
plication, auxiliary  air  pressure  moves  the  piston  full  stroke 
at  once,  auxiliary  air  passes  by  the  removed  corner  of  the 
slide  valve  through  emergency  port  and  on  top  of  the 
emergency  piston,  pushing  it  down,  this  opens  the  emer- 
gency valve  and  allows  train  pipe  air  to  pass  into  the  brake 
cylinder,  which  sudden  reduction  of  train  pipe  pressure 
operates  the  next  triple  quick  action  and  so  on  throughout 
the  whole  train.  At  the  same  time  auxiliary  air  passes 
through  the  tail  port  in  the  slide  valve;  also  some  air 
passes  by  the  emergency  piston  into  brake  cylinder  till  the 
pressures  equalize.  When  the  brake  is  set  by  opening  the 
conductor's  valve  or  by  the  train  breaking  in  two,  the 
operation  is  the  same. 

In  releasing  brakes  after  an  emergency  application,  the 
flow  of  air  is  the  same  as  with  a  service  application.  We 
will  add  to  this  answer  the  signal  equipment :  The  main 
reservoir  air  flows  through  the  reducing  valve  till  it 
reaches  a  pressure  of  45  pounds ;  if  the  reducing  valve  is 
adjusted  for  that  pressure.  Air  flows  into  the  air  signal 
pipe  back  to  each  car  discharge  valve.  On  the  engine  it 
passes  from  the  signal  pipe  into  the  upper  part  of  the  sig- 
nal valve  (see  page  125),  over  the  rubber  diaphram  into 
A,  it  also  passes  down  to  the  lower  part  of  the  valve,  up 
by  the  stem  10  slowly  into  chamber  B  until  the  pressure 
equalizes  there  with  the  signal  pipe.  When  the  whistle 
is  to  be  operated  from  the  train,  the  car  discharge  valve 
on  the  car  is  opened,  air  passes  out  of  the  signal  pipe  to  the 
atmosphere.  This  reduces  signal  pipe  pressure,  when  the 
reduction  affects  the  pressure  over  the  diaphram  in  the 
signal  valve,  the  pressure  under  the  diaphram  not  being 
reduced  so  quickly,  air  under  it  in  B  raises  the  diaphram 
and  with  it  the  valve  10,  so  that  air  flows  out  there  to  the 
whistle,  giving  a  blast.  When  the  valve  10  is  raised,  air 
in  B  flows  past  the  flattened  sides  of  this  stem  to  the 
whistle;  this  quickly  reduces  the  pressure  in  B  and  the 


2l8  TRACING   THE   AIR   THROUGH    NEW    YORK    BRAKE 

diaphram  drops,  pushing  valve  10  to  its  seat  so  no  more 
air  passes  to  the  whistle.  As  soon  as  the  train  pipe  pres- 
sure falls  below  45  pounds  the  reducing  valve  opens  and 
begins  to  feed  main  reservoir  air  into  the  signal  pipe 
slowly,  as  the  opening  through  the  valve  is  restricted 
or  choked.  If  the  air  could  pass  into  the  signal  pipe  at  the 
reducing  valve  as  fast  as  it  can  pass  out  at  a  car  discharge 
valve,  no  reduction  would  be  made  in  the  signal  pipe  pres- 
sure. 

With  the  New  York  brake  (see  page  next  Index),  the 
course  of  the  air  is  a  little  different.  Air  flows  from  the 
atmosphere  through  the  receiving  valves  into  the  air  cylin- 
ders as  the  air  pistons  move  up  and  down.  The  air  in  the 
high  presure  air  cylinder  goes  direct  to  the  main  reservoir 
when  it  is  compressed.  The  air  in  the  low  pressure  air 
cylinder,  when  compressed,  passes  into  the  high  pressure 
air  cylinder  and  from  there  into  the  main  reservoir,  thence 
to  the  brake  valve  around  and  on  top  of  the  main  slide 
valve;  main  reservoir  air  goes  to  the  red  hand  of  the  gage 
and  train  pipe  air  to  the  black  hand.  If  a  single  governor 
is  used  it  is  operated  by  train  pipe  air ;  if  a  duplex  governor 
one  side  by  train  pipe  air  and  the  other  by  main  reservoir 
air.  When  in  release  position  it  passes  directly  into  .the 
train  pipe  and  from  the  train  pipe  into  chamber  D  and  the 
supplementary  reservoir  with  the  1902  model  valve.  With 
the  old  style  brake  valve  on  release  position  the  air  in  the 
supplementary  reservoir  and  chamber  D  passes  out  through 
a  small  cavity  in  the  slide  valve  to  the  atmosphere;  this 
allows  train  pipe  pressure  to  move  the  equalizing  piston  to 
its  normal  position.  On  running  position  the  main  reser- 
voir air  passes  by  the  excess  valve  and  then  into  the  train 
pipe;  train  pipe  air  passes  into  the  supplementary  reservoir 
with  the  brake  valve  in  this  position. 

The  train  pipe  air  passes  back  through  the  train  pipe 
to  each  triple  valve  that  is  cut  in.  At  the  triple  valve  the 
air  passes  through  the  port  F  in  the  vent  valve  piston  and 
if  the  main  piston  is  not  already  in  release  position,  moves 
it  there.  Air  then  passes  through  the  feed  groove  into  the 


TRACING   THE   AIR  2IQ 

auxiliary  until  the  pressure  there  has  equalized  with  the 
train  pipe. 

With  a  service  application,  the  slide  valve  in  the  brake 
valve  is  moved  till  the  service  port  is  open,  train  pipe  air 
then  flows  direct  to  the  atmosphere  until  its  pressure  is  re- 
duced so  the  presure  of  the  air  in  the  supplementary 
reservoir  can  move  the  piston,  closing  the  cut-off  valve 
and  stopping  the  escape  of  train  pipe  air. 

This  reduction  of  train  pipe  pressure  extends  to  each 
triple,  auxiliary  air  pressure  moves  the  triple  piston,  gradu- 
ating valve  and  slide  valve;  first  closing  the  feed  groove, 
next  the  exhaust  port  and  then  opening  the  air  port  so  air 
passes  from  the  auxiliary  to  the  cylinder.  The  air  in  the 
space  G,  between  the  main  triple  piston  and  the  vent  valve 
piston  passes  out  through  port  F  so  the  vent  valve  piston 
does  not  move  in  a  service  application. 

In  an  emergency  application  the  slide  valve  in  the 
brake  valve  is  moved  to  emergency  position.  Train  pipe 
air  passes  rapidly  out  through  the  large  ports  in  the  slide 
valve,  reducing  train  pipe  pressure  so  rapidly  that  the  triple 
pistons  make  a  quick  stroke.  As  the  air  between  the  two 
pistons  cannot  pass  through  port  F  quickly  enough,  the 
vent  valve  piston  moves  with  the  main  piston,  unseats  the 
vent  valve;  this  allows  train  pipe  air  to  flow  to  the  atmos- 
phere. The  air  also  pushes  against  the  quick  action  pis- 
ton, moving  it  over  and  with  it  opens  the  quick  action 
valve,  which  permits  auxiliary  air  to  flow  through  the  pas- 
sages into  the  cylinder,  the  check  valve  preventing  this  air 
from  flowing  back  from  the  cylinder.  Auxiliary  air  also 
flows  into  brake  cylinder  through  the  service  port  at  the 
graduating  valve.  In  releasing  the  brake  the  flow  of  air 
has  already  been  described. 

The  course  of  air  through  the  signal  equipment  is  the 
same  as  described  with  Westinghouse  signal,  except  that 
air  passes  from  chamber  A  to  chamber  B  through  a  small 
port  b  when  charging  up  the  signal  valve,  and  out  of  B 
around  the  plug  4  to  chamber  A  when  the  signal  valve 
operates. 


AIR  BRAKE  EXAMINATION  QUESTIONS. 

1.  What    are    the    essential    parts    of    the    automatic 
brake?     What  does  each  part  do? 

2.  Can  you  trace  the  course  of  the  steam  through  the 
steam  end  of  the  air  pump?     Can  you  trace  the  course  of 
the  air  through  the  pump? 

3.  How  should  the  pump  be  started  and  lubricated? 

4.  If  the  pump  stops  after  working  good   for  a  time, 
where  is  the  trouble  likely  to  be? 

5.  If  it  makes   a   quick   stroke   one   way   and   a   slow 
stroke  the  other  where  is  the  trouble  likely  to  be? 

6.  What  are  the  principal  causes  for  a  pump  running 
hot? 

7.  What  damage  does  it  do  to  a  pump  if  it  gets  very 
hot? 

8.  If   the   main    reservoir    is    partly   filled   with    water 
which    will    it   affect    the    most,    setting   or    releasing    the 
brake?     Why?     How  often  should  it  be  drained? 

9.  What  might  prevent  the  governor  shutting  off  the 
steam  and  stopping  the  pump  when  maximum  pressure  is 
obtained  ? 

10.  Where  would  you  look  for  the  trouble  if  governor 
stops  the  pump   at  much  less  than  standard  pressure? 

11.  If  too  much  oil  is  used  in  the  air  end  of  pump  is  it 
likely  to  gum  up  governor  so  it  will  not  work  accurately? 

12.  Should  you  test  the  engine  and  tender  equipment 
for  leaks? 

13.  How  do  you  test  for  leaks  in  main  reservoir  and 
pipes  from  pump  to  brake  valve? 

14.  What  other  parts  of  the  equipment  gets  air  from 
the  main  reservoir  besides  the  train  pipe? 

15.  How   do  you   test   for   a   leak   in   train   pipe?     In 
signal  line? 

16.  How  do  you  locate  a  leak  that  lets  off  the  brake? 

17.  What  pressure  should  you  have  before  testing? 


EXAMINATION   QUESTIONS  221 

18.  What  controls   the  excess  pressure  with  the   H-5 
brake  valve?     With  the  F-6  valve? 

19.  How  many  kinds  of  engineers  brake  valves  have 
we  in  service  on  this  road? 

20.  Can  you  trace  the  air  through  each  of  them? 

21.  Explain  the  principle  of  operation  of  the  engineers 
equalizing  discharge  brake  valve? 

22.  Describe    its    operation    to    apply   the    brake   with 
service    or    emergency   applications,   and    in    releasing   the 
brake. 

23.  Where  is  the  excess  valve,  and  the  feed  valve  lo- 
cated in  the  engineer's  brake  valve7 

24.  Why  is  it  necessary  to  keep  these  valves  clean  and 
regulated  for  the  proper  pressure?     How  is  this  done? 

25.  Why  is  excess  pressure  necessary?     Do  you  need 
the  most  with  a  large  main  reservoir  or  a  small  one7 

26.  Is  more  excess  needed  to  release  all  the  brakes  on 
a  long  train  than  on  a  short  one? 

27.  How  do  you  regulate  the  excess  pressure  with  a 
"  D-8  brake  valve  ?    With  the  1892  model  or  F-6  valve  ? 

28.  Name  the  different  positions  of  the  brake  valve. 

29.  What  ports  are  open  and  what  ports  are  closed  in 
each  position? 

30.  Where    does    main    reservoir    pressure    begin    and 
end? 

31.  Where  does  train  pipe  pressure  begin  and  end? 

32.  Where  does  auxiliary  pressure  begin ? 

33.  What  is  the  equalizing  port  for*J     Is  ii  open  in  all 
positions  of  the  brake  valve? 

34.  Do  leaks  in  the  brake  valve  affect  the  operation  of 
the  brakes?     Explain  how. 

35.  Do  you  consider  a  cut  rotary  valve  or  seat  dan- 
geious? 

36.  Will  using  the  valve, in  emergency  instead  of  ser- 
vice application  cause  this  cutting  any  quicker?     Why? 

37.  With  the  D-8  valve  does  the  black  hand  show  the 
same    pressure    when    valve    is    in    emergency    position? 
Why? 


222  EXAMINATION   QUESTIONS 

38.  Does  the  1892  model  valve  sjiow  the  pressure  this 
way?     Why? 

39.  If  the  equalizing  piston  becomes  gummed  or  sticks, 
how  will  it  affect  its  operatiota  iri  applying  the  brakes? 

40.  What  is   the  purpose  of  tb^'  small   reservoir  con- 
nected to  the  equalizing  discharge  valve? 

41.  If  the  pipe  leading  fr£>m  valve  to  .small  reservoir  is 
broken  off  or  leaking  ba^ry,  ^hat  will  you  do? 

42.  Where   is   the  jjtst   alL  taken   from   in    making   a 
service  stop? 

43.  What  port  does  ffc^)low  out  of? 

44.  Where  next  does  it  come  from?     Where  next? 

45.  Does  air  ever  blow  out  of  train  'pipe  exhaust  when 
releasing  the  brake?     Why? 

46.  Do  you  hear   it  when  releasing  brake  on   engine 
and  tender  only?    ^Do  you^fcear  it  with  a  train  of  over 
two  cars  ? 

47.  If  you  are  connected  to  more  than  two  air  cars 
and  heard  that  blow,  what  would  it  indicate? 

48.  How  do  you  know  that  the  brake  valve  is  working 
properly  ? 

49.  When  applying  the  brakes  can  you  tell  about  how 
many  cars  are  connected  with  air  to  the  brake  valve  by  the 
amount  of  air  escaping  from  the  train  pipe  exhaust? 

50.  How  much  do  you  reduce  the  train  pipe  pressure 
form  seventy  pounds  to  set  the  brake  as  tight  as  possible? 

51.  Why  will  this  reduction  do  that? 

52.  Does    the   length   of   travel   of   brake   piston   have 
anything  to  do  with  the  pressure  when  brake  is  full  set? 
How?     Explain  fully. 

53.  In   making  a   service   stop   why  should  the  brake 
valve  not  be  moved  past  the  service  application  position? 

54.  Is  this  movement  of  the  brake  valve  liable  to  kick 
off  some  of  the  head  braks?     Why? 

55.  What  is  the  proper  position  to  place  brake  valve  in 
after  releasing  brakes  if  they  are  to  be  set  again  immedi- 
ately?    Why?     Explain  fully. 

56.  What  are  the  functions  or  uses  of  the  triple  valve? 

57.  How  many  forms  in  use  on  this  road?     Describe 
each  form. 


NATION   QUESTIONS  223 

58.  Where  dJ^all  the  air  come  from  that  enters  the 
brake  cylinder  thrJ|jb  the  plain  triple  when  setting  the 
brake? 

59.  Does  all  the 'air  that  goes  into  the  brake  cylinder 
of  a  quick  acting  brake  come  from  the  auxiliary 

60.  Please  explain  the  action  of  the  quick  action  triple 
when  used  in  the  emergence  application. 

61.  Can  you  get  the  en|Bfency  action  after  a  service 
application  ? 

62.  Does  it  take  a  suH  |T  reduction  of  pressure  right 
at  the  triple  to  work  the  qurejraction  valves  or  will  a  slow, 
heavy  reduction  do  this?     Why? 

63.  If  three  or  four  cars  at  the  heao^end  of  the  train 
do  not  have  quick  action  triples  working,  can  you  get  the 
emergency  application  behind  these  cars  by  a  reduction  at 
the  brake  valve?  %  fc 

64.  What  is  the  function  of  the  graduating  valve? 

65.  Where  is  it  located  and  how  does  it  operate? 

66.  If  the  graduating  valve  leaks  on   its   seat  is  the 
brake  connected  to  that  triple  liable  to  release  on  a  partial 
application?    On  a  full  application?    Why  is  this? 

67.  How  will  the  quick  action  triple  work  if  the  gradu- 
ating pin  is  broken?     How  will  you  locate  the  defective 
brake? 

68.  What  is  the  function  of  the  graduating  stem  and 
spring  ? 

69.  If  this  spring  is  very  weak  or  missing  how  will  it 
affect  the  work  of  the  triple  valve  ? 

70.  How   does   the  air   get   from  the   train   pipe   into 
the   auxiliary? 

71.  Why  is  this  port  so  small?     Could  the  brakes  be 
set  and  released  as  certainly  on  a  long  train  if  this  port 
was  much  larger?    Would  auxiliaries  charge  evenly? 

72.  In  what  position  of  the  triple  valve  is  the  port 
open? 

73.  How  rapidly  does  an  empty  auxiliary  charge  up 
to  seventy  pounds  with  seventy  in  the  train  pipe? 

74.  How    rapidly    from    fifty    pounds    up    to    seventy 
pounds  ? 


224  EXAMINATION     QUESTIONS 

75.  What  regulates  the  time  of  charging  each  different 
sized  auxiliary? 

76:  If  one  auxiliary  is  charged  up  higher  than  another 
is  the  brake  likely  to  creep  on?  Is  it  liable  to  take  place 
when  coupling  up  an  air  brake  train?  Explain  why. 

77.  Why  is  it  dangerous  to  apply  and  release  the  brake 
repeatedly  in  making  one  station  stop? 

78.  Does  this  apply  to  a  release  and  second  application 
at  a  slow  speed  on  slippery  track  ?   With  a  passenger  train  ? 
With  a  freight  train? 

79.  Do  you  understand  that  brake  cylinders  have  leak- 
age grooves?     Where  are  they  located  and  how  long  are 
they?     What  are  they  for? 

80.  Do  you  allow  for  them  when   setting  the  brake? 
How? 

81.  As  a  rule  how  much  reduction  in  train  pipe  pres- 
sure is  necessary  to  ensure  that  brake  piston  goes %  past  the 
leakage  groove? 

82.  Does  a  long  train  require  more  than  a  short  train? 
Why? 

83.  What  should  be  done  after  coupling  to  an  air  brake 
train  before  pulling  out? 

84.  What  pressure  should  you  have  in  train  pipe  and 
auxiliaries  before  testing  the  brake? 

85.  How  do  you  know  when  you  have  seventy  pounds 
in  the  auxiliaries? 

86.  What  tests  of  air  equipment  are  called  for  by  our 
rules  ? 

87.  Explain  fully  how  these  tests  should  be  made. 

88.  Are  you  required  to  test  retaining  valves?    How  is 
this    done? 

89.  If  a  brake  is  broken  or  disabled  how  will  you  pre- 
vent it  working  on  that  car  and  let  the  brakes  work  on 
other  cars? 

90.  How    do    you    cut    out    the    brake    on    engine    or 
tender? 

91.  Is  it  necessary  to  release  the  brake  before  cutting 
it  out? 

92.  How  does  the  length  of  the  piston  travel  affect  the 
work  of  the  brake?     If  it  is  too  long?     If  it  is  too  short? 


EXAMINATION   QUESTIONS  225 

93.  What  is  the  proper  piston  travel?     For  passenger 
cars?     For  freight  cars?     For  engine  brakes? 

94.  How  is  the  slack  taken  up  to  secure  this  adjust- 
ment? 

95.  Should  the  triple  be  cut  out  before  adjusting  the 
levers  to  avoid  injury  to  the  workman  in  case  brake  goes 
on? 

96.  At  what  travel  should  the  driver  brake  piston  be 
adjusted? 

97.  How  is  the  slack  of  a  six  wheel  brake  taken  up? 

98.  What  is  necessary  in  order  to  have  all  the  brakes 
work  alike? 

99.  When  brakes  go  on  suddenly  and  are  not  operated 
by  the  engineer  what  should  you  do?     To  what  causes 
would  you  assign  this? 

100.  If  an  air  brake  train  breaks  in  two  how  do  you 
proceed  to  get  train  ready  to  go  ahead  again? 

101.  How  do  you  proceed  in  case  of  a  bursted  hose? 
How  can  you  help  trainmen  to  locate  it? 

102.  Would  it  be  necessary  in  these  cases  to  make  a 
terminal  test? 

103.  After  releasing  the  train  brake  there  is  a  steady 
leak    from    the    exhaust   port    of    the    triple,    what    is    the 
trouble  ? 

104.  What  precautions  must  be  observed  in  making  a 
stop  with  a  "  part  air  "  freight  train  ?     What  with  a  long, 
"full  air"  train? 

105.  In  making  a  stop  with  a  freight  train  when  would 
you  let  off  the  brakes  to  make  a  smooth  stop?     Why? 

106.  When  with  a  passenger  train?    Why? 

107.  What  is  the  pressure  retaining  valve,  what  is  its 
use  and  how  is  it  operated? 

108.  How  many  pounds  of  air  is  it  intended  to  close 
up  on  and  hold  in  the  brake  cylinder? 

109.  Does   the   brake    release   any    slower   till    it   gets 
down  to  this  pressure,  and  how  is  it  done? 

no.  Can  you  get  the  emergency  action  of  the  brake 
with  the  pressure  retainers  holding  fifteen  pounds? 

in.  In  descending  a  grade  how  can  you  best  keep  a 
train  under  control  ? 


226  EXAMINATION     QUESTIONS 

112.  When  two  or  more  engines  are  coupled  together 
which  one  should  do  the  braking? 

113.  Can  both   engineers  use  the  brakes  at  the  same 
time  safely? 

114.  How  will   you   proceed  to   give  the   leading  en- 
gineer complete  control  of  the  train?     What  should  the 
second  engineer  do  ? 

115.  If   there   is   no   cut   out   cock   on   second   engine 
under  the  brake  valve  what  should  be  done? 

116.  How  does  the  air  signal  equipment  operate? 

117.  What   pressure   should   be   carried   in  the   signal 
line?     How  do  you  know  you  have  this  pressure? 

118.  What  causes  the  whistle  to  blow  each  time  the 
brake  is- released?    What  makes  it  repeat  the  signal? 

119.  Will   a   leak   in  the  train   signal   pipe   affect  the 
working  of  the  whistle?     Explain. 

120.  Explain  the  meaning  of  the  signals  given  by  one, 
two,  three  and  four  blasts  of  the  signal  whistle. 

121.  What  changes  do  you  make  in  the  engine  equip- 
ment to  carry  no  pounds  train  pipe  pressure  instead  of 
70,  for  the  high  speed  brake? 

122.  How  many  pounds  train  pipe  reduction  in  a  ser- 
vice application  will  give  a  fully  applied  high  speed  brake? 

123.  Is  it  safe  to  use  the  emergency  application  of  the 
high    speed   brake   when    running   less   than    30   miles    an 
hour?     Why? 

124.  Explain   the   action   of   the   high    speed   reducing 
valve  in  service,  and  in  emergency. 

125.  What  pressures  should  be  in  the  brake  cylinders 
on  the  engine  and  tender  when  the  Straight  Air  brake  is 
fully  applied? 

126.  How  is  this  pressure  regulated? 

127.  Does  long  piston  travel  have  any  effect  in  reduc- 
ing this  pressure?  • 

128.  What   valve   closes    the   exhaust   from   the   brake 
cylinder  to  the  triple  when  the  Straight  Air  is  applied,  and 
vice  versa? 

129.  Is  it  good  practice  to  use  the  automatic  while  the 
Straight  Air  is  full  set  on  the  engine  and  tender  brake? 
Why? 


EXAMINATION    QUESTIONS  227 

130.  Should  the  Straight  Air  brake  valve  be  left  on 
lap  position  while  operating  the  automatic?     Why? 

131.  How  many  air  pipe  connections  at  the  Distribut- 
ing valve?     Explain  where  the  air  comes  from  and  goes 
to  at  each  of  these  connections. 

132.  Explain  the  effect  of  leaks   from   each  of  these 
pipes  and  tell  what  you  would  do  in  each  case,  if  any  of 
them  break  off. 

133.  What  is  the  duty  of  the  equalizing  piston  and  its 
slide  valves  in  the  Distributing  valve,  and  what  air  pres- 
sures operate  it? 

134.  What  is  the  duty  of  the  application  piston  and 
its  valves  and  what  air  pressures  operate  it? 

135.  Why  does  the  engine  brake  creep  on  when  either 
brake  valve  is  lapped?     How  will  you  locate  this  defect? 

136.  Will  the  engine  brake  stay  applied  if  both  brake 
valves  are  in  running  position?     Why?     Will  it  creep  on 
from  leaks? 

137.  Which   brake   valve   is   used   to   apply   the   auto- 
matic  brake   on   train   and   engine?     Which   brake   valve 
should  be  used  to  operate  the  engine  brake  only? 

138.  What  is   the   difference  in  the  operation  of  the 
engine  brake  by  the  Independent  brake  valve  and  by  the 
Straight  Air  brake  valve? 

139.  Does  the  safety  valve  on  the  Distributing  valve 
control  the  application  chamber  pressure  when  the  Inde- 
pendent brake  valve  is  used?     Or  in  an  automatic  applica- 
tion only? 

140.  What  valve  regulates  the  brake  cylinder  pressure 
in  a  full  application  by  the  Independent  brake  valve? 

141.  Explain  the  operation  of  the  excess  pressure  side 
of  the  duplex  pump  governor. 

142.  Is    it   necessary    to    move   the    New    York   brake 
valve  to  positive  lap  position  at  a  train  pipe  reduction,  or 
should  the  valve  be  allowed  to  move  itself  to  automatic 
lap?     Why? 

143.  Trace    the   course   of    the    train   pipe   air   in   the 
Westinghouse  quick  action   triple   in   release,   service   and 
emergency    positions.      Also    do    the    same    for    the    New 
York  quick  action  triple  valve. 


INDEX. 


Air  Pump —  8      inch  25 

Air  Pump —  gl/2  inch  27 

Air  Pump — n       inch    ,. 31 

Air  Pump — Cross  Compound   36 

Air  Pump — New  York  Duplex 169  to  173 

Air  Signal    124-126-134-207-209 

Adjusting  brake  22-131 

Auxiliary  reservoir  22-44-93-114 

Automatic  slack  adj  uster 151 

B-4  feed  valve 63 

Breaking  in  two 121 

Bursted  hose  121 

Brakes  creeping  on 65-108 

Brakes  sticking 106-132-136 

Brakes  leaking  off 22-70-103-105-133 

Brake  leverage  21-155-162 

Charging  auxiliaries 6-21-22-112 

Cutting  out  brakes 1 17-132 

Cam  driver  brake  leverage 159 

Calculating  air  pressures 163 

Compensating  valve   205 

Distributing  valve 79  to  86 

Double  heading  73-75-101-120 

Defective  air  pump  31-41-174 

Defective  governor  40-178 

Defective  piston  packing   33-36-105-133-174 

Defective  brake  valve    59-62-71-74-104-184 

Defective  triple  valve 17-102-106-203 

Defective  train  pipe   in 

Defective  brake   105-132-136 

Defective  air  signal  124-134 

Definitions    23 

Equalizing  discharge  brake  valve 11-50-75 

Equalizing  reservoir  22-53-71-166 

Excess  pressure  48-49-106-181 

Excess  pressure  pump  governor 43-77 

Emergency  application   14-23-98-130-182-199 

Equalization   5-18-19-163 

Examination  questions  220  to  227 

F-6  brake  valve 52  to  57 

F-6  feed  valve 57  to  59 

Full  application  10-23-93 

Governor   39-56-109-137-176 


PAGE 

G-6  feed  valve 60  to  62 

Graduating  valve  7-92-101-104-197 

Graduated  application 7-92-107 

General  arrangement  of  brake 44-168-214 

H-5  brake  valve 75 

Handling  trains  on  grades 1 18-213 

High  Speed  brake 140  to  148 

High  pressure  control 149 

Independent  brake  valve 78 

Inspection  of  brake  equipment 21-45-112 

Leakage  groove 22-92-115 

Leaks  in  train  pipe 46-108-136 

Leaks  in  brake  cylinder 22-105-133 

Leaks  in  triple  valve 108-123-132-135-203 

Leaks  in  brake  valve 59-62-70-73-104-184 

Leaky  train  pipe  check  valve 104-122-203 

Operating  the  equipment 21-91-109-118-210 

Overcharging  train  pipe 19-106-109 

Pump  governor 39-56-77-109-146-176 

Piston  travel   18-22-116-131-133 

Pressure  on  brake  piston 18-93-114-116-164-200 

Position  of  brake  valve 11-64-66-74-90-91-183 

Plain  triple   valve 5-6-94-117-132 

Pressure  retaining  valve 122-129-139 

Quick  action  triple  valve 15-18-98-100-195 

Quick  service  triple  valve I7-Q4 

Releasing  brakes   9-107-110-121-192-213 

Reducing  valve   125-142-208 

Straight  air  brake *. 86  to  90-186 

Slide  valve  feed  valve 60  to  64 

Slack  adjuster 150  to  15} 

Service  application 7-23-92-182-198 

Testing  for  leaks    46-59-73-103-105-175-184-203 

Testing  air  signal 46-124-127 

Testing  brake  valve  70-73-104-184 

Testing  brakes    20-72-104-112-120 

Two-application  stop   19-111 

Train  pipe  pressure 22-46-49-64-106 

Train  men's  questions ^ 128  to  140 

Tracing  the  air 214 

Water  raising  system 138 

New  York  Duplex  pump  168 

New.  York  brake  valve,  1902  model 178 

New  York  brake  valve  B-2  model , 189 

New  York  accelerator  valve   192 

New  York  Quick  action  triple  valve 195 

New  York  Compensating  valve  205 


MITCHELL'S  MODELS 

ARE  THE  ROCK  BALLAST  ROAD 
TO    AIR-BRAKE     KNOWLEDGE 


No  person  interested  in  air-brakes  can  afford  to  be 
without  a  set  of  Mitchell's  Air=BraKe  Models. 


BECAUSE: 

They  contain  just  what  you  should  know. 

They  make  the  subject  of  air-brakes  easy. 

They  greatly  shorten  the  time  necessary  for  acquir- 
ing air-brake  knowledge. 

They  make  study  a  pleasure  instead  of  drudgery. 

They  enable  you  to  get  knowledge  with  the  least  ex- 
penditure of  time  and  labor. 

They  insure  your  getting  the  necessary  knowledge. 

They  cost  so  little,  and  are  so  thorough  and  complete. 


For  further  information  write  for  free  illustrated  cir- 
cular of  Mitchell's  Models,  containing  also,  valuable 
air-brake  information. 


INTERNATIONAL    CORRESPONDENCE    SCHOOLS, 

SCRANTON,    PENNSYLVANIA. 


Q.  Why  should  Dixon's  Air  Brake  and  Triple 
Valve  Grease  be  used  for  lubricating  the  air 
brake  system? 

A.  Because  in  actual  service  it  has  been 
found  that:  weather  conditions  affect  it  but 
slightly;. even  in  the  coldest  weather  it  will  not 
stiffen  and  result  in  emergency  action  of  the 
brakes  when  service  application  is  wanted.  It 
does  not  gum,  ball-up,  dry,  nor  collect  at  back 
end  of  cylinders,  gathering  dirt  and  clogging 
feed^  grooves.  It  provides  lubrication  for  engi- 
neer's brake  valve,  triple  valves,  brake  cylinders 
and  pistons.  Write  for  free  sample. 

JOSEPH  DIXON  CRUCIBLE  CO,, 

Jersey  City,  N.  J. 

TLJ    |T  
n  ci 


TRAVELING  ENGINEERS  ASSOCIATION 

At  their  annual  meetings  in  September  in  each  year 
since  1893  have  had  carefully  prepared  Committee 
Reports  on  a  great  number  of  practical  questions 
concerning  the  operation  of  the  locomotives  and  its 
various  attachments  like  the  lubricator,  injector  and 
air  brake,  as  well  as  the  proper  handling  of  trains. 
The  Committee  Reports,  together  with  the  discus- 
sion thereon  by  the  members  of  the  Association,  are 
printed  for  distribution  to  others  who  wish  to  in- 
form themselves  on  these  important  topics.  Copies 
of  these  Reports  for  each  year  since  1894  are  on 
sale  at  the  office  of  the  secretary.  Price,  50  cents  for 
paper  bound;  $1  for  the  leather  covers.  Reports  for 
-  the  meetings  of  1893  and  1894  are  all  gone.  Address, 

W,  0.  THOMPSON,   Secretary,   Oswego,  N.  Y. 


THE  AMERICAN 
AUTOMATIC  SLACK  ADJUSTER 


Manufactured    by 


THE 


AMERICAN  BRAKE  COMPANY, 

St.  Louis,  Mo.,  U.  S.  A. 


STAR  BRASS  MANUFACTURING  GO, 


Air  Brake 

Inspectors' 

Gages, 


The  above  illustration  represents  a  very  useful  article 
that  we  have  recently  produced  for  the  assistance  of  the 
Air  Brake  Inspector  to  instantly  determine  the  pressure  or 
test  the  signal  apparatus  by  attaching  to  the  hose  couplings 
of  the  rear  coach,  as  it  will  fit  either  the  brake  or  signal 
couplings.  These  features  obviate  the  necessity  of  the 
inspector  consulting  the  air  guage  in  the  cab,  and  the  great 
advantage  that  this  very  useful  instrument  affords  will  readily 
be  seen.  The  Test  Guage  is  only  2£  inches  in  diameter  and 
weighs  less  than  one  pound.  They  are  exclusively  made  by 
us  and  prices  will  be  forwarded  upon  application. 

Also  original  and  exclusive  manufacturers  of 

Westinghouse  Duplex  Air  and  Locomotive  Gages 

Fitted  with  our  Patent  Non-Corrosive  movement  and 
Non-Setting  corrugated  spring  tubes. 

Open  and  Muffled  Locomotive  Pop  Safety  Valves. 
Extra  Heavy  Water  Gages.  Gage  CocKs,  Lubricators,  etc 


MAIN  OFFICE  AND  WORKS  : 

108=1 14 E.Dedham  St., Boston,  Mass. 


28  New  Bridge  St.,  70  Cortland  St., 

London,  E.  C.,  England.  New  York  City 


PALMETTO 
Am  PUMP  PACKING 

IN   SETS   READY  FOR  USE. 


DOES 
NOT 
GET 
HARD 


FOR    BOTH    PUMPS. 


ASK    THE 

LARGE 
RAILWAY 
SYSTEMS 

WHAT 
THEY  THINK 

OF 
PALMETTO 


N.     Y.     DUPLEX 
PUMP 


OIL  PUMPS   NOT   NECESSARY  TO   KEEP  PALMETTO   SOFT 
SAMPLES    FURNISHED    FREE. 


GREEN,  TWEED  &  Co. 

SOLE   MANUFACTURERS 
1O9    DUANE    STREET,    NEW   YORK. 


Locomotive  Engine  Running 
and  Management 

By  Angus  Sinclair, 

A  book  that  has  probably  helped  more  enginemen 
than  any  other.  Practical,  reliable  and  brought  up- 
to-date.  Twenty-first  edition  ready.  Price,  $2.00. 


Firing  Locomotives 

By  Angus  Sinclair. 

Is  a  very  readable,  elementary  treatise  on  combustion, 
suitable  for  the  pocket.  It  contains  as  much  ready 
information  as  many  bigger  books.  Price,  50  cents. 


Locomotive  Boilers 

By  Henry  J.  Baps. 

A  practical  book  on  the  care  and  management  of  loco- 
motive boilers.  Ought  to  be  in  the  pocket  of  every 
person  concerned  in  the  subject.  Also  a  good  chapter 
on  oil  burning.  Price,  50  cents. 


Twentieth  Century  Locomotives 

By  Angus  Sinclair  Company. 

It  has  670  pages  dealing  with  the  designing,  construction,  re- 
pairing and  operating  of  modern  locomotives.  Work  shop 
operations,  care  and  management  of  engines.  Quick  repairs  on 
the  road,  shop  tools,  shop  recipes,  train  resistance  and  power 
calculations,  definitions  and  tables.  Standard  types  of  engines 
illustrated  and  described.  Fully  indexed.  Most  all  round  use- 
ful modern  compendium  of  the  locomotive.  $3.00. 


FOR    SALE    BY 


Railway  and  Locomotive  Engineering 

136  Liberty  Street,  MEW  YORK 


BRAKEMAN'S 
AIR  BRAKE  AND  SIGNAL  COCK 

For  Controlling  from  Rear  of  Trains  When  Backing. 


THE  methods  of  handling  trains  at  terminals  and  passen- 
ger yards  have  entirely  changed  within  a  few  years  and 
it  is  now  a  universal  practice  that  trains   be   backed 
into  the  station  and  from  there  to  the  yards.     This  makes  it 
necessary  to  have  them  positively  controlled    from    the    rear 
end.    It  is  also  necessary  to  have 
a  substitute  for  the  engine  bell, 
as    a   warning    in    passing    into 
stations  and  yards. 

The  cut  shows  a  device  which 
is  designed  to  fulfill  these  re- 
quirements. It  is  a  combined 
plug-cock  and  alarm  whistle  (A) 
attached  by  a  short  length  of 
hose  or  pipe  to  the  "train  pipe" 
of  the  rear  car.  The  whistle  is 
blown  by  pressing  the  button  (B) 
shown  in  the  cut,  which  allows 
air  to  pass  through  the  hollow 
handle  of  the  cock  to  whistle, 
which  is  shown  on  the  end  of 
the  handle,  blowing  the  same 
and  giving  the  necessary  alarm. 
The  air  used  for  this  purpose, 
on  account  of  the  design  of  the 
whistle  valve,  POSITIVELY 
does  not  affect  the  brake 
system. 

By  moving  the  handle  of   the 
cock  in  either  direction  exhaust 
is   made   from    the    train    pipe, 
through   opening   C,    the    brake 
set,  and  consequent  positive  con- 
trol of  the  train  given. 
The  device  is  also  valuable  in  switching  of  freight   trains, 
especially  during  the  night  or  in  thick  weather,  as  the  train 
by  its  use  is  under  complete  control  from  both  ends. 


SHERBURNE  &  CO., 

Sole  Manufacturers. 

53  Oliver  Street,  BOSTON,  MASS.,  U.  S.  A. 


The  Gollmar  Bell  Ringer  No.  2 

MANUFACTURED  BY  THE  U.  S.  METALLIC  PACKING  CO., 

429  North  Thirteenth  St.,  PHILADELPHIA,  PA. 

INSTRUCTIONS. 

Fasten  the  bracket  to  the 
boiler  on  right  hand  side  of 
bell  frame.  Place  the  ringer 
as  low  as  possible  and  in  di- 
rect line  with  the  center  of 
bell  yoke.  When  the  bell  yoke 
is  at  rest  fasten  the  crank  31 
so  that  the  pin  will  be  about 
1^  inch  forward  of  central  line 
of  ringer.  Set  screw  30  should 
always  be  set  tight.  The 
connection  should  be  as  long 
as  possible,  the  inside  part  of 
connecting  rod  36  not  less  than 
5  inches  inside  of  crank  box 
35.  The  governor  bolt  33  with 
jamb  nut  34  is  used  to  regulate 
the  stroke  of  the  bell  and  if 
properly  adjusted  will  prevent 
bell  from  whirling.  If  bell 
whirls  when  throttle  is  wide 
open  unscrew  governor  bolt 
33  and  if  it  does  not  ring  hard 
enough  screw  it  farther  down 
making  connecting  rod  longer. 
Care  must  be  used  to  keep 
from  making  it  too  long  to 
work.  Jamb  nut  34  should 
always  be  set  tight.  Always 
use  air,  never  steam.  Valve 
adjuster  set  screw  47  should 
be  set  up  tight  enough  to  keep 
the  valve  to  its  seat  without 
blowing.  Use  red  lead  spar- 
ingly at  joints  and  only  on 
outside  of  pipes.  Blow  out 
the  pipes  with  steam  or  air 
under  high  pressure  before 
coupling  pipes  to  ringer.  In 
short,  use  the  same  precau- 
tions that  should  be  used  in 
putting  up  air  brakes.  When  ringer  is  new  it  will  work  stiff 
and  should  be  kept  working  steadily  the  first  few  days. 

Bell  ringers  operated  with  air  at  90  pounds  up  to  120  pounds  and  found 
perfect  and  correctly  adjusted  before  shipment. 


LIVES 

MONEY 

Collisions 


CHEAPER 

AND  than 

More  Reliable 


OIL 


I  AT  I  OTTOl! 

ELECTRIC 

ri§»/      HEADLIGHT  CO. 

1427  MONADNOCK,    CHICAGO 


Chicago  Locomotive  Lubricator 

Class  "C" 

3-Feeds  with  Solid  Sight  Feed  Glasses 


83 


62- 


63 


To  Operate 

Open  steam  valve  full  at  boiler.  Open  valve  62  one 
turn.  Open  water  valve  73  three  turns.  Note  the  feed 
glasses  to  see  if  filled  with  water.  After  the  glasses  are 
filled  with  water  regulate  feed  with  valve  3  I . 

The  auxiliary  oil  cup  65,  close  pressure  valve  62. 
See  that  valve  7  8  is  closed.  Open  auxiliary  drain  valve 
88  to  free  cup  of  water.  Open  auxiliary  filler  plug  66 
and  fill.  After  cup  is  filled,  open  feed  valve  78  wide. 
This  auxiliary  cup  can  be  operated  with  steam  on  lubri- 
cator and  engine  throttle  open. 

Write  us  for  full  descriptive  pamphlets. 

The  Ohio  Injector  Co. 

1437  Monadnock  Block,  Chicago,  111. 


Locomotive   Management 

Breakdowns  and  their  Cures. 


By   DONALD   R.   McBAIN, 

Michigan  Central  Railroad. 


Bound  in  Two   Styles.  Flexible  Leather,    75  cents, 

Cloth  Bound,    50  cents. 


Send  for  a  copy.     It  is  full  of  practical  pointers  from 
a  practical  man. 


For  Sale  by  D.  R.  McBAIN,  Jackson,  Michigan. 


Books  on  Approval? 

If  you've  ever  spent  your  good  money  for 
books  that  didn't  suit  after  you  got  'em, 
you'll  appreciate  our  plan.  We  send 


ANY    MECHANICAL    BOOK    PUBLISHED 

Costing   a    dollar   or    more,    anywhere    in 
North    America   on   approval. 

IF  IT  SUITS     SEND   THE    MONEY 


IF  NOT     SEND  BACK  THE    BOOK 

We  carry  a  large  stock  and  supply  any  book  in  print 
at  the  regular  price.    We  represent  and  are  represented 
by  The  Locomotive  Publishing  Co.,  Ltd.,  London.    Ask  us 
about  anything   you    want   to    know.      Charts,  models,         V 
maps,  etc.    Catalogs,  of  course. 

THE    DERRY-COLLARD   COMPANY 

109  LIBERTY  STREET,   NEW  YORK. 


rof 


YA  01^02 


T  FA- 2.0 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 


